# ETH key-management technology: exchanges, custodians, ETFs Compiled 2026-10-29. Companion machine-readable file: `custody_tech_exchanges_custodians.json`. ## Purpose and classes The goal is to classify how each entity's ETH is secured, so that on-chain balances (where MPC wallets look like ordinary EOAs) can be split into MPC/TSS and everything else. Classes: - **MPC/TSS**: threshold signing; the full ECDSA key is never assembled. - **Shamir / key sharding with reconstruction**: key split into shards that are recombined to sign. This is not MPC. - **HSM single key with quorum/policy**: the whole key lives inside an HSM or encrypted blob and is released or used after approvals. This is not MPC. - **Smart-contract multisig**: a contract address on-chain (Safe, BitGo WalletSimple). - **Hybrid**: a mix, with the split given where stated. - **Unknown**. `mpc_share_*` estimates the share of that entity's ETH held in MPC/TSS-controlled addresses. Ranges are deliberately wide where the evidence is marketing or indirect. ## Most consequential findings 1. **Coinbase Custody Trust, the custodian for most US spot-ETH-ETF ETH, is documented in current SEC filings as key sharding with reconstruction, not MPC.** Grayscale's FY2025 ETHE 10-K (filed 2026-02-25) and GDLC 10-K (filed 2026-09-03) both say that "Multiple private key shards held by the Custodian must be combined to reconstitute the private key to sign any transaction". Coinbase's own FY2025 10-K says "the cryptographic consensus of multiple human approvers is required to **decrypt a private key** for both hot and cold wallets". That language does not fit MPC, where no whole key exists to decrypt. - Counter-evidence: in Aug 2024 Coinbase's head of cryptography said Coinbase "Vaults" use MPC (offline share, human-approver share and server shares) and are being rolled out across custody and exchange. The cb-mpc library is "based on the MPC library used at Coinbase to protect cryptoassets". - No filing gives the migration share. Coinbase is therefore classed Hybrid with a low MPC best guess (about 15-25%) and a very wide range. This is the largest single uncertainty in the whole estimate: Coinbase held about $56B of ETH on platform at 2025-12-31, roughly 19M ETH, and ETF ETH comes on top in CCTC. 2. **Anchorage is HSM, not MPC.** Keys are generated and used in air-gapped HSMs with quorum logic. A Grayscale filing (2026-10-05) also describes Anchorage key shards being combined to reconstitute keys. Porto, its self-custody wallet, likewise decrypts a single private key with 2-of-3 recovery shares. 3. **BitGo is a genuine hybrid, and the split can be measured on-chain.** ETH multisig wallets are WalletSimple contracts, while MPC/TSS wallets (ETH TSS since about 2022-23, MPCv2/DKLs23 since 2024) keep their base balance in an EOA. Custody (cold) is offered in both multisig and MPC forms. BitGo's FY2025 10-K gives no split. The prior is mostly multisig for legacy and institutional ETH, and MPC for newer wallets. Measure WalletSimple contract balances directly. 4. **Binance is probably TSS but has never disclosed it.** Binance built and audited tss-lib in 2019. Aumasson and Shlomovits (2020) state that "the leading cryptocurrency exchange (in transaction volume) adopted TSS to protect some of its wallets" and that they attacked "the cold wallet system of the biggest cryptocurrency exchange". No post-2021 primary source exists, so confidence is low. 5. **Robinhood is MPC plus hardware security according to its 10-K, using an unnamed vendor.** Gemini uses HSMs for cold storage with "MPC technology" somewhere in the stack. 6. **OKX cold storage is encrypted single keys, not MPC.** Keys are "encrypted using AES" and "decryption is first performed on encrypted private keys" before signing on offline devices. 7. **Bybit's ETH cold wallet was a Safe multisig before the Feb 2025 hack.** Afterwards Bybit says it uses the "MPC model" and "consolidated HSM", with no split given. 8. **ETF custody is concentrated at Coinbase.** At 2026-06-30, US spot ETH ETFs held about 5.28M ETH (sum of the 10-Q figures below, excluding the newly launched MSSE). About 4.75M of that (90%) was at Coinbase Custody as sole or primary custodian: ETHA, ETHB, ETHE, ETH, ETHW, EZET and QETH. ETHV (Gemini primary) and TETH (Coinbase, BitGo and Anchorage) split theirs. FETH (476k ETH) was FDA-only at 2026-06-30 but added Anchorage and BitGo as custodians in an Aug 2026 prospectus. Several funds now stake most of their ETH. Staked ETH sits in validators, and what is controlled is the withdrawal-credential key and the custodian's signing setup. 9. **Clear MPC custodians:** Copper, Fireblocks and Fireblocks Trust Co, Ceffu (TSS with shares on air-gapped HSMs; the source dates from 2022), Cobo, and BNY (built on Fireblocks per 2022 coverage). **Clear HSM, non-MPC custodians:** Anchorage, Fidelity Digital Assets, Zodia, Hex Trust, Paxos, Taurus/State Street, and Ledger Enterprise. 10. **Exchanges with documented vendor MPC:** - Deribit uses Fireblocks MPC for hot wallets plus some cold storage; the rest of its cold storage is at Coinbase Prime Custody. - Bitvavo uses Fireblocks for hot wallets; its cold storage is at Coinbase Custody International and Copper. - Bitso uses Fireblocks. - Bitfinex has a large ETH cold wallet (about 531k ETH in one EOA, per an unverified label). It is described as "multisignature ... approval ... via three of five HSMs". On Ethereum that must be off-chain quorum, so it is classed HSM/quorum, with MPC possible. 11. **Non-US ETPs:** segregated ETH products found hold about 0.56M ETH, mostly at BitGo, Coinbase, Zodia and Komainu. Hong Kong, CI Galaxy, 3iQ, WisdomTree and iShares Europe custodians remain unverified. 12. **Caveat on prospectus boilerplate.** Since May 2025, 21Shares and Morgan Stanley prospectuses say their custodians (Coinbase, BitGo, Anchorage, BNY) use "a combination of Multi-Party Computation, HSMs and Cross-Domain Security". The language is generic and not attributed to any custodian, so it is weak evidence for any one of them. ## Method notes for the on-chain side - MPC wallets, HSM single-key wallets, Shamir-reconstructed keys and plain EOAs all look identical on-chain. Only Safe and WalletSimple (or other contract wallets) are distinguishable, because they are contracts. - **BitGo:** WalletSimple base wallets and forwarders are contracts. BitGo MPC wallets (v3/v5 with forwarders, v6 native) hold their base balance in an EOA. - **Staked ETH (ETFs, exchanges):** the relevant key is whatever controls the 0x01 or 0x02 withdrawal-credential address. For a custodian, that is usually the same custody stack as its cold storage. - **Coverage gap:** the shared web-search budget ran out during research. The following are Unknown largely for lack of searches, not because of negative evidence: Bithumb, Korbit, Coinone, MEXC, KuCoin, HTX, BingX, WhiteBIT, Standard Custody, Bitcoin Suisse, the Hong Kong ETFs, CI Galaxy, 3iQ, WisdomTree and iShares Europe. Korean-language and regulatory sources (FSC/FSS, DNB, CNBV) were not searched. - **Quotes:** marked "search-engine snippet" where the page could not be fetched directly and the quote was taken from search results. Re-verify those before citing. ## Summary table | Entity | Segment | ETH key-management class | MPC share best (low-high) | Confidence | ETH held (ETPs) | |---|---|---|---|---|---| | Coinbase (consolidated: retail exchange + Prime + Custody Trust) | exchange | Hybrid (legacy encrypted/sharded single key with reconstruction + in-house MPC 'Vaults' rolling out) | 25% (5%-70%) | low | | | Coinbase retail cold storage (Coinbase, Inc. omnibus) | exchange | Shamir/key sharding with reconstruction (legacy) transitioning to MPC Vaults (Hybrid) | 25% (5%-70%) | low | | | Coinbase hot wallets | exchange | Hybrid (likely increasingly MPC; filings still describe key decryption) | 50% (10%-90%) | low | | | Binance | exchange | MPC/TSS (in-house) - probable, undocumented by Binance itself | 65% (25%-95%) | low | | | Bybit (before 2025-02-21 hack) | exchange | Smart-contract multisig on Ethereum (cold) + unknown hot | 5% (0%-20%) | high | | | Bybit (after Feb 2025) | exchange | Hybrid (MPC + HSM, per Bybit press release; split not stated) | 60% (20%-95%) | low | | | OKX | exchange | HSM/encrypted single key with quorum access (NOT MPC) for cold; hot 'multi-signature' scheme undocumented (likely key-splitting, not on-chain multisig for ETH) | 10% (0%-40%) | medium | | | Upbit (Dunamu) | exchange | Unknown (in-house; post-incident review of HSM and MPC systems reported) | 20% (0%-60%) | low | | | Robinhood (Robinhood Crypto / RHEU; excl. Bitstamp) | exchange | MPC/TSS (vendor technology integrated in-house, combined with HSM) | 90% (60%-100%) | medium | | | Gemini (exchange) | exchange | Hybrid (HSM-based cold storage; MPC used for some wallets) | 15% (0%-50%) | low | | | Bitget | exchange | Hybrid (MPC for platform wallets per Bitget announcement; cold-wallet tech not specified) | 50% (20%-90%) | low | | | Crypto.com | exchange | Hybrid | 50% (20%-90%) | low | | | KuCoin | exchange | Unknown | 30% (0%-80%) | low | | | Gate (Gate.io) | exchange | Hybrid | 35% (10%-80%) | low | | | HTX (Huobi) | exchange | Unknown | 15% (0%-60%) | low | | | Bithumb | exchange | Unknown | 20% (0%-70%) | low | | | MEXC | exchange | Unknown | 30% (0%-80%) | low | | | Bitstamp (Robinhood) | exchange | Smart-contract multisig | 15% (5%-50%) | medium | | | Bitpanda | exchange | HSM-based or encrypted single key with quorum/policy approval | 10% (0%-40%) | low | | | Deribit (Coinbase) | exchange | Hybrid | 55% (30%-85%) | medium | | | Bitvavo | exchange | Hybrid | 50% (25%-80%) | medium | | | Korbit | exchange | Unknown | 20% (0%-70%) | low | | | Coinone | exchange | Unknown | 20% (0%-70%) | low | | | BingX | exchange | Unknown | 20% (0%-70%) | low | | | WhiteBIT | exchange | Unknown | 20% (0%-70%) | low | | | Bitso | exchange | MPC/TSS | 70% (40%-95%) | medium | | | Bitfinex | exchange | HSM-based or encrypted single key with quorum/policy approval | 20% (0%-60%) | low | | | Kraken (exchange + Kraken Custody/Kraken Financial) | exchange | Hybrid | 35% (10%-70%) | low | | | Coinbase Wallet-as-a-Service / CDP embedded & server wallets (non-custodial) | exchange (wallet infra) | MPC/TSS (in-house, cb-mpc) | 100% (90%-100%) | high | | | Coinbase Custody Trust Company (CCTC; ETF custodian) | custodian | Shamir/key sharding with key reconstruction (NOT MPC) per current SEC filings; some MPC Vault use possible | 15% (0%-60%) | medium | | | Coinbase Prime (institutional trading/custody) | custodian | Hybrid (custodial vault = CCTC sharded keys; Prime Onchain/Web3 wallet = MPC, client-controlled) | 20% (5%-60%) | low | | | Anchorage Digital (Anchorage Digital Bank N.A.) | custodian | HSM-based single key with quorum/policy approval (NOT MPC) | 2% (0%-10%) | high | | | BitGo (all trust companies + self-custody platform) | custodian | Hybrid (WalletSimple smart-contract multisig + TSS/MPC EOA wallets); share not disclosed | 25% (10%-50%) | low | | | Copper (Copper.co, incl. ClearLoop) | custodian | MPC/TSS (in-house) | 95% (85%-100%) | high | | | Fireblocks (platform) | custodian | MPC/TSS (vendor) | 90% (75%-100%) | medium | | | Fireblocks Trust Company (NY) | custodian | MPC/TSS (vendor) | 95% (80%-100%) | medium | | | Ceffu (ex-Binance Custody) | custodian | MPC/TSS (in-house) | 95% (80%-100%) | medium | | | Cobo | custodian | MPC/TSS (in-house) | 85% (60%-100%) | medium | | | Komainu | custodian | Hybrid | 30% (10%-60%) | low | | | Zodia Custody | custodian | HSM-based single key with quorum/policy approval (not MPC) | 5% (0%-20%) | medium | | | Hex Trust | custodian | HSM-based single key with quorum/policy approval (not MPC) | 2% (0%-10%) | medium | | | BNY (BNY Mellon Digital Asset Custody) | custodian | MPC/TSS (vendor) | 75% (40%-95%) | low | | | State Street | custodian | HSM-based single key with quorum/policy approval (not MPC) | 5% (0%-30%) | low | | | Gemini Custody (Gemini Trust) | custodian | Hybrid | 35% (10%-70%) | low | | | Paxos (Paxos Trust / national trust bank) | custodian | HSM-based single key with quorum/policy approval (not MPC) | 5% (0%-20%) | medium | | | Standard Custody & Trust (Ripple) | custodian | Unknown | 40% (0%-90%) | low | | | Taurus (Taurus-PROTECT) | custodian | HSM-based single key with quorum/policy approval (not MPC) | 10% (0%-30%) | medium | | | Metaco / Ripple Custody | custodian | Hybrid | 20% (0%-50%) | low | | | Sygnum Bank | custodian | Hybrid | 30% (10%-60%) | low | | | Bitcoin Suisse | custodian | Unknown | 20% (0%-70%) | low | | | Ledger Enterprise (Ledger Vault) | custodian | HSM-based single key with quorum/policy approval (not MPC) | 0% (0%-5%) | high | | | Kraken custody (Kraken Financial) | custodian | Hybrid | 60% (30%-90%) | low | | | Fidelity Digital Assets | custodian | HSM-based single key with quorum/policy approval (not MPC) | 0% (0%-10%) | medium | | | Anchorage Porto (self-custody wallet) | custodian (self-custody software) | HSM-based single key with Shamir-style recovery (NOT MPC) | 0% (0%-10%) | high | | | ETHA (iShares Ethereum Trust) | etf_us | Inherits Coinbase Custody Trust: key sharding with reconstruction per Grayscale filings (NOT MPC), possible partial MPC Vaults | 15% (0%-60%) | medium | 2,695,456 ETH (2026-06-30) | | ETHB (iShares Staked Ethereum Trust) | etf_us | Inherits Coinbase Custody Trust: key sharding with reconstruction per Grayscale filings (NOT MPC), possible partial MPC Vaults; 87% staked (validator withdrawal credentials controlled by custodian) | 15% (0%-60%) | medium | 288,417 ETH (2026-06-30) | | FETH (Fidelity Ethereum Fund) | etf_us | Fidelity Digital Assets (see custodian entry) + Anchorage (HSM) + BitGo (hybrid) | 10% (0%-40%) | low | 476,311 ETH (2026-06-30) | | ETHE (Grayscale Ethereum Staking ETF) | etf_us | Inherits Coinbase Custody Trust: key sharding with reconstruction per Grayscale filings (NOT MPC), possible partial MPC Vaults | 15% (0%-60%) | medium | 774,999 ETH (2026-06-30) | | ETH (Grayscale Ethereum Staking Mini ETF) | etf_us | Inherits Coinbase Custody Trust: key sharding with reconstruction per Grayscale filings (NOT MPC), possible partial MPC Vaults | 15% (0%-60%) | medium | 854,643 ETH (2026-06-30) | | ETHW (Bitwise Ethereum ETF) | etf_us | Inherits Coinbase Custody Trust: key sharding with reconstruction per Grayscale filings (NOT MPC), possible partial MPC Vaults | 15% (0%-60%) | medium | 106,742 ETH (2026-06-30) | | EZET (Franklin Ethereum ETF) | etf_us | Inherits Coinbase Custody Trust: key sharding with reconstruction per Grayscale filings (NOT MPC), possible partial MPC Vaults | 15% (0%-60%) | medium | 20,464 ETH (2026-06-30) | | QETH (Invesco Galaxy Ethereum ETF) | etf_us | Inherits Coinbase Custody Trust: key sharding with reconstruction per Grayscale filings (NOT MPC), possible partial MPC Vaults | 15% (0%-60%) | medium | 9,782 ETH (2026-06-30) | | ETHV (VanEck Ethereum ETF) | etf_us | Gemini (HSM cold storage, some MPC) + Coinbase Custody | 15% (0%-50%) | low | 48,972 ETH (2026-06-30) | | TETH (21Shares Ethereum Staking ETF; formerly CETH) | etf_us | Mixed: Coinbase (sharded key) + BitGo (multisig/MPC) + Anchorage (HSM) | 15% (0%-50%) | low | 8,185 ETH (2026-06-30) | | MSSE (Morgan Stanley Ethereum Trust) | etf_us | BNY (see custodian entry) + Coinbase Custody; prospectus lists 'MPC, HSMs and CDS' generically | 30% (0%-80%) | low | n/a (launched 2026-07 (no 10-Q yet)) | | 21Shares Ethereum Staking ETP (AETH) | etf_non_us | Hybrid | 10% (0%-40%) | medium | 121,456 ETH (2026-10-28) | | 21Shares Ethereum Core Staking ETP (ETHC) | etf_non_us | Hybrid | 10% (0%-50%) | medium | 46,755 ETH (2026-10-28) | | CoinShares Ethereum Staking ETP (ETHE, ex-CETH; GB00BLD4ZM24) | etf_non_us | Hybrid | 15% (0%-40%) | low | 164,372 ETH (2026-10-27/28) | | CoinShares XBT Provider Ether Tracker One (SEK) / Ether Tracker Euro (COINETH, COINETHE) | etf_non_us | Unknown | 15% (0%-60%) | low | 207,955 ETH (2026-10-28) | | Bitwise Physical Ethereum ETP (ZETH) | etf_non_us | Hybrid | 10% (0%-40%) | medium | 40,107 ETH (2026-10-22) | | Bitwise Ethereum Staking ETP (ET32) | etf_non_us | Hybrid | 10% (0%-40%) | medium | 76,244 ETH (2026-10-22) | | VanEck Ethereum ETN (VETH, DE000A3GPSP7) | etf_non_us | Unknown | 20% (0%-80%) | low | 70,118 ETH (2026-10-28) | | WisdomTree Physical Ethereum | etf_non_us | Unknown | 15% (0%-60%) | low | n/a (None) | | iShares Ethereum ETP (Europe) | etf_non_us | Unknown | 10% (0%-60%) | low | n/a (None) | | Purpose Ether ETF (ETHH, Canada) | etf_non_us | Hybrid | 10% (0%-50%) | low | 119,521 ETH (2026-10-28) | | Fidelity Advantage Ether ETF (FETH, Canada) | etf_non_us | HSM-based single key with quorum/policy approval (not MPC) | 0% (0%-10%) | medium | 25,019 ETH (2026-10-28) | | CI Galaxy Ethereum ETF (Canada) | etf_non_us | Unknown | 10% (0%-60%) | low | n/a (None) | | 3iQ Ether Staking ETF (ETHQ, Canada) | etf_non_us | Unknown | 10% (0%-60%) | low | n/a (None) | | ChinaAMC Ethereum ETF (HK) | etf_non_us | Unknown | 30% (0%-90%) | low | n/a (None) | | Harvest Ethereum ETF (HK) | etf_non_us | Unknown | 30% (0%-90%) | low | n/a (None) | | Bosera HashKey Ethereum ETF (HK) | etf_non_us | Unknown | 30% (0%-90%) | low | n/a (None) | ## Exchanges ### Coinbase (consolidated: retail exchange + Prime + Custody Trust) - **Class:** Hybrid (legacy encrypted/sharded single key with reconstruction + in-house MPC 'Vaults' rolling out) - **MPC share of ETH (best / low / high):** 25% / 5% / 70%; confidence: low - **Hot:** Encrypted single key decrypted by approver quorum per 10-K; MPC 'Vaults' being rolled in (2024+) - **Cold:** Key shards reconstituted to sign (per Grayscale 10-Ks); MPC Vault migration in progress, extent undisclosed - **Notes:** Coinbase reported $56.2B of ETH in assets on platform at 2025-12-31 (10-K AOP table), roughly 19M ETH at the year-end price. Its own FY2025 10-K describes decrypting a private key with approver consensus, which is incompatible with pure MPC, where no full key exists to decrypt. Lindell (2024) says Vaults use MPC with an offline share, a human-approver share and server shares, but gives no migration share. Treat Coinbase as the single largest swing factor. - **Evidence:** - [2026-02-12] primary (Coinbase FY2025 10-K): "A key risk mitigation measure we utilize is ensuring that wallet private keys are never stored in plaintext format in any location. The cryptographic consensus of multiple human approvers is required to decrypt a private key for both hot and cold wallets." - [2026-02-25] primary (Grayscale Ethereum Staking ETF FY2025 10-K describing Coinbase Custody Trust): "Once generated, private keys are encrypted, separated into “shards”, and then further encrypted. ... Multiple private key shards held by the Custodian must be combined to reconstitute the private key to sign any transaction in order to transfer the Trust’s Ether." - [2024-08-08] secondary (Cointelegraph report of Yehuda Lindell talk, SBC 2024): "“There is one share for the offline environment, one share for human approvers, and one share for each MPC server,” Lindell said. ... Vaults “are used and will be used for more products at Coinbase, for custody, exchange, and more”" - [2025-03 (repo README, accessed 2026-10-29)] primary (Coinbase GitHub): "This cryptographic library is based on the MPC library used at Coinbase to protect cryptoassets, with modifications to make it suitable for public use." - [undated, accessed 2026-10-29] primary (marketing page): "More than cold storage, Coinbase Vault storage combines physical security, consensus computation, and strict process controls into one world-class solution." ### Coinbase retail cold storage (Coinbase, Inc. omnibus) - **Class:** Shamir/key sharding with reconstruction (legacy) transitioning to MPC Vaults (Hybrid) - **MPC share of ETH (best / low / high):** 25% / 5% / 70%; confidence: low - **Hot:** n/a - **Cold:** Same key-management stack as Coinbase consolidated; 10-K: 'decrypt a private key' by approver consensus; geographically distributed key material - **Notes:** No Coinbase disclosure splits retail vs institutional key technology. 10-K target is at most 2% of AUC in hot wallets. - **Evidence:** - [2026-02-12] primary (Coinbase FY2025 10-K): "A key risk mitigation measure we utilize is ensuring that wallet private keys are never stored in plaintext format in any location. The cryptographic consensus of multiple human approvers is required to decrypt a private key for both hot and cold wallets." - [2026-02-12] primary: "Cold wallet private key materials are stored and secured at facilities within the United States and internationally." - [undated (historical account)] secondary (historical): "Coinbase once generated the keys to its cold storage inside Faraday-caged tents ... The keys themselves were then split using Shamir's secret sharing." - [2024-08-08] secondary (Cointelegraph report of Yehuda Lindell talk, SBC 2024): "“There is one share for the offline environment, one share for human approvers, and one share for each MPC server,” Lindell said. ... Vaults “are used and will be used for more products at Coinbase, for custody, exchange, and more”" ### Coinbase hot wallets - **Class:** Hybrid (likely increasingly MPC; filings still describe key decryption) - **MPC share of ETH (best / low / high):** 50% / 10% / 90%; confidence: low - **Hot:** 10-K: approver consensus 'to decrypt a private key for both hot and cold wallets'; Lindell 2024: MPC Vaults intended to replace hot/cold wallets; cb-mpc derived from Coinbase production MPC - **Cold:** n/a - **Notes:** Hot wallets hold at most about 2% of AUC per the 10-K, so this sub-segment matters little for supply share. - **Evidence:** - [2026-02-12] primary (Coinbase FY2025 10-K): "A key risk mitigation measure we utilize is ensuring that wallet private keys are never stored in plaintext format in any location. The cryptographic consensus of multiple human approvers is required to decrypt a private key for both hot and cold wallets." - [2024-08-08] secondary (Cointelegraph report of Yehuda Lindell talk, SBC 2024): "“There is one share for the offline environment, one share for human approvers, and one share for each MPC server,” Lindell said. ... Vaults “are used and will be used for more products at Coinbase, for custody, exchange, and more”" - [2025-03 (repo README, accessed 2026-10-29)] primary (Coinbase GitHub): "This cryptographic library is based on the MPC library used at Coinbase to protect cryptoassets, with modifications to make it suitable for public use." ### Binance - **Class:** MPC/TSS (in-house) - probable, undocumented by Binance itself - **MPC share of ETH (best / low / high):** 65% / 25% / 95%; confidence: low - **Hot:** TSS (in-house tss-lib, GG18/GG20 lineage) believed used for at least some wallets - **Cold:** Academic paper (2020) states the biggest exchange's cold wallet system used TSS; no current Binance disclosure - **Notes:** Binance has never published how it secures exchange ETH. The evidence is circumstantial: it built and audited tss-lib in 2019, CZ promoted TSS as 'far superior to multi-sig', and the 2020 paper says the top exchange used TSS for its cold wallet. That paper predates 2021. Binance's MPC wallet product and Ceffu are separate. On-chain, Binance ETH sits in EOAs, which fits MPC or single-key equally well. - **Evidence:** - [2020-09 (ePrint 2020/1052)] primary academic (Aumasson & Shlomovits, 'Attacking Threshold Wallets'); exchange not named but by volume in 2020 = Binance: "the leading cryptocurrency exchange (in transaction volume) adopted TSS to protect some of its wallets. ... one of our targets is the cold wallet system of the biggest cryptocurrency exchange (which has been fixed after our disclosure)." - [2019-10 (audit), accessed 2026-10-29] primary (Binance/BNB Chain open-source threshold ECDSA library): "A full review of this library was carried out by Kudelski Security and their final report was made available in October, 2019." - [2019-11-06] secondary; quote taken from search-engine snippet, not re-verified on page: "TSS is implemented off-chain, unlike multi-signature protection, thereby using fewer resources and reducing potential attack surfaces." ### Bybit (before 2025-02-21 hack) - **Class:** Smart-contract multisig on Ethereum (cold) + unknown hot - **MPC share of ETH (best / low / high):** 5% / 0% / 20%; confidence: high - **Hot:** Unknown (EOAs) - **Cold:** Safe{Wallet} smart-contract multisig (proxy at 0x1Db92e2EeBC8E0c075a02BeA49a2935BcD2dFCF4, 3-of-6 per most analyses) - **Notes:** 401,347 ETH was drained from this Safe on 2025-02-21. Historical entry only. - **Evidence:** - [2025-03-10] secondary (NCC Group forensic analysis): "Bybit Cold Wallet: 0x1Db92e2EeBC8E0c075a02BeA49a2935BcD2dFCF4 ... The Gnosis Safe (masterCopy) contract has all the logic. It allows arbitrary transactions that have been signed by the predefined number of whitelisted signers." - [2025-03-18] secondary; quote taken from search-engine snippet, not re-verified on page: "the transaction included valid signatures from 3 of 6 signers" ### Bybit (after Feb 2025) - **Class:** Hybrid (MPC + HSM, per Bybit press release; split not stated) - **MPC share of ETH (best / low / high):** 60% / 20% / 95%; confidence: low - **Hot:** Unknown - **Cold:** Bybit says it adopted 'more stringent cold wallet solutions' using the MPC model and consolidated HSMs - **Notes:** On-chain check worth doing: if Bybit's current large ETH cold addresses are EOAs rather than Safe contracts, that supports the MPC/HSM claim. The release does not say whether the HSMs hold MPC shares or whole keys. - **Evidence:** - [2025-06-04] primary (Bybit press release via PR Newswire): "Bybit has since adopted more stringent cold wallet solutions to minimize the attack surface ... increased wallet protection using the MPC (Multi-Party Computation) model ... consolidating HSM (Hardware Security Modules) to achieve hardware-level safety" ### OKX - **Class:** HSM/encrypted single key with quorum access (NOT MPC) for cold; hot 'multi-signature' scheme undocumented (likely key-splitting, not on-chain multisig for ETH) - **MPC share of ETH (best / low / high):** 10% / 0% / 40%; confidence: medium - **Hot:** 'Semi-offline multi-signature' signing; keys 'randomly generated, encrypted' in volatile memory, multiple personnel to access - **Cold:** Private keys generated offline, AES-encrypted, decrypted on offline devices to sign; backups in separate vaults - **Notes:** OKX Learn pages mention 'multi-signature and MPC' in a layered approach without detail. The OKX Web3 wallet (MPC/seedless) is a separate, non-custodial product. - **Evidence:** - [undated, accessed 2026-10-29] primary: "Cold wallet addresses with private keys are generated on offline devices where they are encrypted using Advanced Encryption Standard (AES). Unencrypted versions of the private keys are never stored. ... For cold wallet withdrawals, decryption is first performed on encrypted private keys. The transactions are then signed on the offline devices" - [undated, accessed 2026-10-29] primary: "Semi-offline multiple signature mechanisms are adopted for transaction signing." ### Upbit (Dunamu) - **Class:** Unknown (in-house; post-incident review of HSM and MPC systems reported) - **MPC share of ETH (best / low / high):** 20% / 0% / 60%; confidence: low - **Hot:** In-house wallet system; Nov-2025 Solana hot-wallet theft traced to a flaw letting attackers infer private keys from on-chain signatures - **Cold:** Unknown technology; >98% of holdings in cold storage per Dunamu after the incident - **Notes:** Upbit is probably among the largest ETH holders after Binance and Coinbase, but nothing public describes its cold-key technology. Korean-language FSC/FSS sanction documents from 2026 may hold detail. - **Evidence:** - [2025-11-28] secondary (The Block reporting Upbit statement); quote taken from search-engine snippet, not re-verified on page: "an emergency audit found a flaw that could let attackers mathematically reconstruct certain wallet private keys" - [2025-12] secondary; quote taken from search-engine snippet, not re-verified on page: "While Upbit already holds 98.33% of its cryptocurrency holdings [in cold wallets], the exchange's owner company aims to decrease its hot wallet holdings to below 1%" - [2025-12] secondary (low quality); quote taken from search-engine snippet, not re-verified on page: "Upbit began reviewing its internal wallet infrastructure, including hardware security modules (HSMs) and multi-party computation (MPC) systems." ### Robinhood (Robinhood Crypto / RHEU; excl. Bitstamp) - **Class:** MPC/TSS (vendor technology integrated in-house, combined with HSM) - **MPC share of ETH (best / low / high):** 90% / 60% / 100%; confidence: medium - **Hot:** MPC + hardware security architecture, third-party vendor technology - **Cold:** Same architecture; offline cold wallets in US and EU - **Notes:** The vendor is not named. Bitstamp, now a Robinhood subsidiary, uses third-party custodians; see the Bitstamp entry. - **Evidence:** - [2026-02-18] primary (Robinhood FY2025 10-K): "Our wallets store and transfer all the settled digital assets listed in the Glossary of Terms above using an architecture combining multi-party computation and hardware security to eliminate a single point of failure." - [2026-02-18] primary: "we do integrate proprietary technology from a third-party industry-standard vendor into the systems we use to support the custody, transfer and settlement operations to our wallets." ### Gemini (exchange) - **Class:** Hybrid (HSM-based cold storage; MPC used for some wallets) - **MPC share of ETH (best / low / high):** 15% / 0% / 50%; confidence: low - **Hot:** MPC technology referenced - **Cold:** Geographically distributed HSMs supporting offline cold storage - **Notes:** The 10-K does not say which wallets are MPC. Gemini Custody is covered in the custodian section. - **Evidence:** - [2026-03-31] primary (Gemini FY2025 10-K): "Our infrastructure features geographically distributed Hardware Security Modules (“HSM”) supporting cold storage, as well as MPC technology." - [2026-03-31] primary: "Our secure custody solutions safeguard user assets using offline cold storage, geographically distributed Hardware Security Modules (HSMs), and multi-party computation (MPC) technology." ### Bitget - **Class:** Hybrid (MPC for platform wallets per Bitget announcement; cold-wallet tech not specified) - **MPC share of ETH (best / low / high):** 50% / 20% / 90%; confidence: low - **Hot:** Platform wallets upgraded to MPC key-splitting across servers (Jan 2024) - **Cold:** Cold wallets described as multi-signature access (secondary); institutional clients may use Cobo MPC - **Notes:** 'Dividing private keys into segments' could describe true MPC or Shamir splitting. The Bitget Wallet 2-of-3 TSS is a separate non-custodial product. - **Evidence:** - [2024-01-26] secondary (reporting Bitget press release): "The cryptocurrency exchange Bitget has enhanced the security of its platform wallets ... The technology implemented by Bitget works by dividing private keys into segments across multiple servers." - [2026-02-02] secondary; quote taken from search-engine snippet, not re-verified on page: "stores most of its customers' funds offline in cold wallets, which are safeguarded by multi-signature access" ### Crypto.com - **Class:** Hybrid - **MPC share of ETH (best / low / high):** 50% / 20% / 90%; confidence: low - **Hot:** Unknown - no primary statement on hot-wallet signing tech - **Cold:** Hybrid/uncertain - historically Ledger Vault (HSM + quorum, not MPC) for cold storage (2019-2021); Crypto.com Custody now states proprietary in-house MPC 'tested through our group businesses' - **Notes:** MPC statement is for the Custody product, not explicitly the retail exchange omnibus wallets. No post-2021 confirmation that Ledger Vault is still used. Address 0x46340b20830761efd32832A74d7169B29FEB9758 (label 'Crypto.com 2' from memory, unverified) is an EOA holding ~21k ETH, so this wallet is not a smart-contract multisig. - **Evidence:** - [undated, accessed 2026-10-29] primary: "Crypto.com Custody employs a proprietary multi-party computation (MPC) cryptography-based solution to protect private keys. Our multi-layer security has been rigorously tested through our group businesses over the years" - [undated, accessed 2026-10-29] primary: "We have strict controls on access rights to funds in both cold and hot wallets." - [2021-09] secondary: "The coverage guarantees reimbursement of direct and indirect losses of assets in the cold storage Ledger Vault — Crypto.com's custodial partner." ### KuCoin - **Class:** Unknown - **MPC share of ETH (best / low / high):** 30% / 0% / 80%; confidence: low - **Hot:** Unknown - Sept 2020 hack was attributed to leaked hot-wallet private keys (single-key hot wallets at that time); wallets redeployed after - **Cold:** Unknown - no public tech disclosure found - **Notes:** The quote is from a search-result summary of the KuCoin CEO recap. It was not fetched verbatim. KuCoin security and proof-of-reserves pages say nothing about key-management tech. - **Evidence:** - [2020-09] secondary: "the leakage of the private key of KuCoin hot wallets" ### Gate (Gate.io) - **Class:** Hybrid - **MPC share of ETH (best / low / high):** 35% / 10% / 80%; confidence: low - **Hot:** Hybrid - Gate says hot wallets use multi-signature and MPC; no split given - **Cold:** Unknown implementation - Gate says 'offline, multi-signature cold wallets', but sampled ETH cold address is an EOA (so not a Safe-type contract; could be MPC/TSS or HSM quorum) - **Notes:** 'Multi-signature' on an ETH EOA has to be off-chain, either MPC/TSS or quorum-gated single-key signing. On-chain check: 0x1C4b70a3968436B9A0a9cf5205c787eb81Bb558c (label 'Gate.io 3' from memory, unverified) is an EOA with ~20k ETH. Gate pages were fetched via WebFetch summarisation, so quotes may need a re-check. - **Evidence:** - [undated, accessed 2026-10-29] primary: "Our hot wallets incorporate multi-signature and Multi-Party Computation (MPC) technologies, which distribute private key management across multiple parties to eliminate single points of failure" - [undated, accessed 2026-10-29] primary: "Gate uses a cold and hot wallet separation model, keeping the majority of funds in offline, multi-signature cold wallets" ### HTX (Huobi) - **Class:** Unknown - **MPC share of ETH (best / low / high):** 15% / 0% / 60%; confidence: low - **Hot:** Unknown - Sept and Nov 2023 hot-wallet thefts attributed to private-key leakage, which suggests single-key hot wallets then - **Cold:** Unknown - **Notes:** No primary HTX key-management disclosure was found. Quotes are from search-result summaries. - **Evidence:** - [2023-09] secondary: "a substantial loss of $7.9 million" - [2023-11] secondary: "Security firm Cyvers believed the theft was enabled by a private key leak." ### Bithumb - **Class:** Unknown - **MPC share of ETH (best / low / high):** 20% / 0% / 70%; confidence: low - **Hot:** Unknown - **Cold:** Unknown - the Korean rule requires a high cold share (80% under the Virtual Asset User Protection Act enforcement decree since Jul 2024, per my recollection; 70% was the earlier guidance), but the tech is undisclosed - **Notes:** https://www.bithumb.com/react/asset-disclosure exists (likely the statutory asset-custody disclosure) but is a JS app and was not parsed. The web-search budget ran out before Korean-language sources could be checked. - **Evidence:** ### MEXC - **Class:** Unknown - **MPC share of ETH (best / low / high):** 30% / 0% / 80%; confidence: low - **Hot:** Unknown - **Cold:** Unknown - **Notes:** The security page returned 403 and the proof-of-reserves page returned 404. No vendor case study was found. - **Evidence:** ### Bitstamp (Robinhood) - **Class:** Smart-contract multisig - **MPC share of ETH (best / low / high):** 15% / 5% / 50%; confidence: medium - **Hot:** Smart-contract multisig (BitGo) - BitGo case study says warm and hot wallets come from BitGo entities - **Cold:** Smart-contract multisig (BitGo multi-sig custodial cold storage). Robinhood filings confirm Bitstamp uses third-party custodians and also holds some keys internally - **Notes:** The 10-K does not name the custodians. BitGo is named by BitGo's own case study (now removed from the live site and read from the Wayback copy) and by 2019 press. BitGo now also offers TSS/MPC ETH wallets, so part of the balance could be MPC. Robinhood's own (non-Bitstamp) wallets use 'multi-party computation and hardware security'; Bitstamp may migrate to them, which is upside risk. - **Evidence:** - [2026-02-18] primary: "With the exception of Bitstamp (discussed below), we do not utilize third-party custodians for settled cryptocurrencies ... As noted, Bitstamp does use third party custodians." - [2026-10-28] primary: "Bitstamp safeguards its private keys internally and with custodians." - [undated (Wayback capture 2026-03-10)] primary: "Bitstamp leverages BitGo’s multi-signature and custodial cold storage solutions, in addition to warm and hot wallets offered by BitGo’s other entities, to safeguard client assets." ### Bitpanda - **Class:** HSM-based or encrypted single key with quorum/policy approval - **MPC share of ETH (best / low / high):** 10% / 0% / 40%; confidence: low - **Hot:** Unknown, probably the same in-house HSM stack (warm and cold wallets mentioned) - **Cold:** HSM-based with quorum - 95%+ in 'multi-signature cold storage'. Bitpanda's in-house custody stack (BE Custody, ex-Trustology) generates and uses keys only inside FIPS 140-2 L3 HSMs with quorum approvals - **Notes:** The link between the retail exchange's omnibus wallets and the BE Custody HSM stack is inferred, not stated. No MPC claim was found anywhere in Bitpanda materials. - **Evidence:** - [undated, accessed 2026-10-29] primary: "Bitpanda stores 95 %+ of all assets in multi-signature cold storage, so your funds are secured on arrival." - [undated, accessed 2026-10-29] primary: "Wallet-Seeds und Keys für die Verwahrung werden ausschließlich innerhalb von FIPS 140-2 Level 3 Hardware Security Modules generiert und verwendet." - [2026-09-25 (updated)] primary: "BE Custody uses Hardware Security Modules (HSMs) as part of its custody architecture to protect sensitive cryptographic operations and key material." ### Deribit (Coinbase) - **Class:** Hybrid - **MPC share of ETH (best / low / high):** 55% / 30% / 85%; confidence: medium - **Hot:** MPC/TSS (Fireblocks) - withdrawals signed via MPC by Deribit and Fireblocks - **Cold:** Hybrid - Fireblocks MPC self-custody cold vaults plus Coinbase Prime Custody (CCTC), Zodia, BitGo Bank & Trust and Fidelity Digital Assets. Warm wallets: Fireblocks, Coinbase Prime Onchain Wallet, Copper - **Notes:** The split between Coinbase Prime Custody cold (non-MPC per your Coinbase classification) and Fireblocks MPC cold is not given. Hot and warm wallets (<10%) are mostly MPC. Coinbase Bermuda is to be added after Sept 2026 as Deribit integrates into Coinbase, which could lower the MPC share. - **Evidence:** - [2026-10-14 (updated)] primary: "Withdrawal request is broadcasted to the blockchain following MPC signature protocol by Deribit and Fireblocks." - [2026-10-14 (updated)] primary: "Deribit uses Coinbase Prime Custody cold wallets as well as Fireblocks technology for self-custody, MPC, sharded, offline private key system" - [2026-07-14 (updated)] primary: ">90% in Coinbase custody/self-custody and cold self-custody, <10% in self-custody, <1% with third-party custodians" ### Bitvavo - **Class:** Hybrid - **MPC share of ETH (best / low / high):** 50% / 25% / 80%; confidence: medium - **Hot:** MPC/TSS (Fireblocks) - Fireblocks key management for deposit/withdrawal (hot/warm) and treasury operations - **Cold:** Hybrid - the 'vast majority' sits with Coinbase Custody International (non-MPC per your Coinbase classification) and Copper (MPC-based). Bitvavo calls both 'multi-signature' - **Notes:** The Coinbase/Copper split is not disclosed. Insurance limits ($255M Coinbase vs $500M Copper) are only a weak hint. The 'multi-signature' wording is loose, since Copper is MPC-based. - **Evidence:** - [2026-08-12 (updated)] primary: "Bitvavo integrated the custody solutions of Coinbase Custody International" - [2026-08-12 (updated)] primary: "At both custodial partners, multi-signature wallets are used, which require multiple individuals to authorize a transaction before digital assets can be transferred." - [2026-09-28] primary: "Fireblocks provides key management and transaction infrastructure that Bitvavo uses in processing customer deposits and withdrawals." - [2026-09-28] primary: "Security architecture: multi-party computation key management and policy-based transaction authorization" ### Korbit - **Class:** Unknown - **MPC share of ETH (best / low / high):** 20% / 0% / 70%; confidence: low - **Hot:** Unknown - **Cold:** Unknown - **Notes:** korbit.co.kr robots.txt now points to digitalx.miraeasset.com, consistent with Mirae Asset ownership. Address 0xf0bc8FdDB1F358cEf470D63F96aE65B1D7914953 (label 'Korbit' from memory, unverified) is an EOA with ~4,950 ETH. Korean-language sources were not reachable after the search budget ran out. - **Evidence:** ### Coinone - **Class:** Unknown - **MPC share of ETH (best / low / high):** 20% / 0% / 70%; confidence: low - **Hot:** Unknown - **Cold:** Unknown - **Notes:** The help-center API returned 403 and the sitemap has no security page. Korean-language sources were not checked. - **Evidence:** ### BingX - **Class:** Unknown - **MPC share of ETH (best / low / high):** 20% / 0% / 70%; confidence: low - **Hot:** Unknown - Sept 2024 hack (~$43-52M) hit several hot wallets across chains. Halborn infers keys were stored centrally, i.e. not MPC - **Cold:** Unknown - **Notes:** No official post-mortem was found. The Halborn statement is an inference, and the quote is from a search-result summary. - **Evidence:** - [2024-09] secondary: "BingX likely stored copies of its private keys in a single, centralized repository" ### WhiteBIT - **Class:** Unknown - **MPC share of ETH (best / low / high):** 20% / 0% / 70%; confidence: low - **Hot:** Unknown - **Cold:** Unknown implementation - third parties report 96% in cold 'multisignature' wallets - **Notes:** whitebit.com/security returned 403. WhiteBIT's Fireblocks link is Fireblocks Network connectivity, not wallets. - **Evidence:** - [undated, accessed 2026-10-29] secondary: "stores 96% of users' digital assets in cold multi-signature wallets" ### Bitso - **Class:** MPC/TSS - **MPC share of ETH (best / low / high):** 70% / 40% / 95%; confidence: medium - **Hot:** MPC/TSS (Fireblocks) - Fireblocks wallets for operational/exchange wallets - **Cold:** Unknown - no disclosure of cold-storage tech found - **Notes:** This is a vendor case study, not a Bitso or CNBV filing. It does not say whether cold reserves are also in Fireblocks. - **Evidence:** - [2024-05-16] primary: "One of the most important features that Fireblocks provides to us is the ability to have different levels of security and multi-party computation (MPC) architecture in our wallets." ### Bitfinex - **Class:** HSM-based or encrypted single key with quorum/policy approval - **MPC share of ETH (best / low / high):** 20% / 0% / 60%; confidence: low - **Hot:** HSM-based quorum - ~0.5% hot; refills need 4-of-7 HSMs - **Cold:** HSM-based quorum (possibly MPC) - ~99.5% in 'offline, multisignature wallet' approved by 3-of-5 HSMs; main ETH cold address is an EOA, so not smart-contract multisig on Ethereum - **Notes:** On-chain check: 0x742d35Cc6634C0532925a3b844Bc454e4438f44e (widely labelled Bitfinex cold; label from memory) is an EOA with ~531k ETH. So the ETH '3-of-5 multisig' is implemented off-chain, as either TSS/MPC or HSM-gated approval of one key. The text fits HSM quorum better, hence that class. This is a large ETH holder and worth confirming. - **Evidence:** - [2026-05-23 (updated)] primary: "Our cold storage holds about 99.5% of user funds in an offline, multisignature wallet, which requires the approval of all transactions via three of five hardware security modules (HSMs)" ### Kraken (exchange + Kraken Custody/Kraken Financial) - **Class:** Hybrid - **MPC share of ETH (best / low / high):** 35% / 10% / 70%; confidence: low - **Hot:** Unknown - 'advanced cold storage and hot wallet solutions' - **Cold:** Hybrid (Kraken Custody) - Kraken Custody markets 'MPC and HSM-based key storage'. No split given; exchange cold tech undisclosed - **Notes:** No public Payward S-1 was found on EDGAR (FTS check). The custody wording may mean MPC for some flows and HSM for others. - **Evidence:** - [undated, accessed 2026-10-29] primary: "Unparalleled domain expertise in security, cutting-edge MPC and HSM-based key storage and policy enforcement." - [undated, accessed 2026-10-29] primary: "We use advanced cold storage and hot wallet solutions to secure your funds." ## Exchange-operated wallet infrastructure (non-custodial) ### Coinbase Wallet-as-a-Service / CDP embedded & server wallets (non-custodial) - **Class:** MPC/TSS (in-house, cb-mpc) - **MPC share of ETH (best / low / high):** 100% / 90% / 100%; confidence: high - **Hot:** MPC 2-party (user share + Coinbase share) - **Cold:** n/a - **Notes:** These are user-owned addresses, not Coinbase custody, but on-chain they look like EOAs. Listed so the totals do not double-count them. - **Evidence:** - [2023-06-27 (updated 2024-05-15)] secondary (Berkeley MPC deployments list): "Wallets built with WaaS will use MPC for generating signatures on transactions. ... The key is secret-shared between the end user and Coinbase." ## Institutional custodians ### Coinbase Custody Trust Company (CCTC; ETF custodian) - **Class:** Shamir/key sharding with key reconstruction (NOT MPC) per current SEC filings; some MPC Vault use possible - **MPC share of ETH (best / low / high):** 15% / 0% / 60%; confidence: medium - **Hot:** Minimal; ETF assets held in 'Vault Balance' cold storage - **Cold:** Per every Grayscale 10-K (Feb and Sep 2026): keys generated in offline ceremonies, encrypted, split into shards distributed to vaults worldwide; shards 'must be combined to reconstitute the private key' to sign. Coinbase 10-K: 'proprietary combination of software and hardware security modules' - **Notes:** This is the most consequential classification in the set because CCTC custodies most US spot-ETH-ETF ETH (ETHA, ETHB, ETHE, ETH, ETHW, EZET, QETH, part of ETHV/TETH/MSSE). Grayscale's sponsor-certified 10-K text says shards are recombined to reconstitute the key, which is reconstruction and not threshold signing. That boilerplate dates back to about 2018, so Coinbase may have moved some vaults to MPC since then, but no ETF filing says so specifically for Coinbase. - **Evidence:** - [2026-02-25] primary (Grayscale Ethereum Staking ETF FY2025 10-K describing Coinbase Custody Trust): "Once generated, private keys are encrypted, separated into “shards”, and then further encrypted. ... Multiple private key shards held by the Custodian must be combined to reconstitute the private key to sign any transaction in order to transfer the Trust’s Ether." - [2026-09-03] primary (Grayscale CoinDesk Crypto 5 ETF 10-K, custodian = Coinbase Custody Trust): "Multiple private key shards held by the applicable Custodial Entity or Entities must be combined to reconstitute the private key to sign any transaction in order to transfer the Fund’s assets." - [2026-02-12] primary: "For Coinbase Custody Trust Company, LLC (“CCTC”) and Coinbase Luxembourg S.A. ... crypto assets are held separately in dedicated addresses and managed using a proprietary combination of software and hardware security modules." - [2026-07-23] primary (Morgan Stanley Ethereum Trust 424B3; custodians = BNY and Coinbase Custody; generic language not attributed to either custodian; identical boilerplate appears in 21Shares prospectuses since May 2025): "Similarly secure technology used by the Ether Custodians includes a combination of Multi-Party Computation (“MPC”), Hardware Security Modules (“HSMs”), and Cross-Domain Security (“CDS”) to safeguard digital assets." - [2024-08-08] secondary (Cointelegraph report of Yehuda Lindell talk, SBC 2024): "“There is one share for the offline environment, one share for human approvers, and one share for each MPC server,” Lindell said. ... Vaults “are used and will be used for more products at Coinbase, for custody, exchange, and more”" ### Coinbase Prime (institutional trading/custody) - **Class:** Hybrid (custodial vault = CCTC sharded keys; Prime Onchain/Web3 wallet = MPC, client-controlled) - **MPC share of ETH (best / low / high):** 20% / 5% / 60%; confidence: low - **Hot:** Trading balance in Coinbase, Inc. omnibus wallets; same stack as exchange - **Cold:** Vault = CCTC (see above). Prime Onchain Wallet (non-custodial, client-held) is MPC but that ETH is client self-custody - **Notes:** 'Consensus computation' on the Prime custody page is ambiguous marketing. It could describe MPC, quorum decryption, or both. - **Evidence:** - [undated, accessed 2026-10-29] primary (marketing page): "More than cold storage, Coinbase Vault storage combines physical security, consensus computation, and strict process controls into one world-class solution." - [2024-08-08] secondary (Cointelegraph report of Yehuda Lindell talk, SBC 2024): "“There is one share for the offline environment, one share for human approvers, and one share for each MPC server,” Lindell said. ... Vaults “are used and will be used for more products at Coinbase, for custody, exchange, and more”" - [2026-02-25] primary (Grayscale Ethereum Staking ETF FY2025 10-K describing Coinbase Custody Trust): "Once generated, private keys are encrypted, separated into “shards”, and then further encrypted. ... Multiple private key shards held by the Custodian must be combined to reconstitute the private key to sign any transaction in order to transfer the Trust’s Ether." ### Anchorage Digital (Anchorage Digital Bank N.A.) - **Class:** HSM-based single key with quorum/policy approval (NOT MPC) - **MPC share of ETH (best / low / high):** 2% / 0% / 10%; confidence: high - **Hot:** Same HSM platform ('online participation with offline assets') - **Cold:** Keys generated and used inside air-gapped HSMs with custom quorum logic; key backups as shards combined to reconstitute the key (per Grayscale filing) - **Notes:** Porto, Anchorage's self-custody wallet, is also not MPC. Its docs describe encrypted private keys that admins 'decrypt' with 2 of 3 recovery shares, i.e. a single key with Shamir-style recovery. Anchorage is an additional custodian for ETHA, ETHB, ETHE, ETH, FETH and TETH. BlackRock says it has 'no plans' to move ETH there. - **Evidence:** - [undated, accessed 2026-10-29] primary: "Private key material is generated and processed in air-gapped HSMs and is not exported outside the HSM boundary in plaintext." - [undated, accessed 2026-10-29] primary: "Custom logic verifies that each operation has a valid quorum of client approvals as well as Anchorage Digital approval." - [2026-10-05] primary (Grayscale prospectus supplement describing Anchorage): "Multiple private key shards held by the Additional Custodian must be combined to reconstitute the private key required to sign any transaction to transfer the Fund’s assets." - [2025-09-19] primary (21Shares Ethereum ETF prospectus): "Anchorage utilizes hardware security modules that enable online participation with offline assets, unlike traditional cold storage" ### BitGo (all trust companies + self-custody platform) - **Class:** Hybrid (WalletSimple smart-contract multisig + TSS/MPC EOA wallets); share not disclosed - **MPC share of ETH (best / low / high):** 25% / 10% / 50%; confidence: low - **Hot:** Self-custody hot wallets: ETH multisig = WalletSimple smart contract (2-of-3) or MPC/TSS EOA (ETH TSS since 2022-23; MPCv2 = DKLs23) - **Cold:** Custody (cold) wallets offered in both 'Multisig Cold' and 'MPC Cold' for ETH; legacy institutional ETH predominantly WalletSimple - **Notes:** On-chain, this split is measurable. WalletSimple base wallets are contracts deployed by BitGo's factories, and their receive addresses are forwarder contracts. MPC wallets (v3/v5 with forwarders, v6 native) keep their base balance in an EOA. Measure ETH held by BitGo WalletSimple contracts directly and attribute the remainder of BitGo-labelled EOAs to MPC. BitGo's FY2025 AoP was $81.6B (median), with ETH at 10.1%, about $8.2B. That covers custodied and self-custody assets. The prior is that the multisig share is high because institutional and legacy ETH wallets predate ETH TSS and BitGo never force-migrated them. New wallets are steered to MPC. - **Evidence:** - [2026-03-27] primary (BitGo Holdings FY2025 10-K): "We support both a multi-sig protocol and a multi-party computation signature protocol to provide additional layers of security in connection with our wallet solutions. In addition, we hold a significant majority of our clients’ assets in cold storage solutions (over 95% as of December 31, 2025)" - [undated, accessed 2026-10-29] primary (BitGo developer docs ETH support table): "| | Multisig Cold | Multisig Hot | MPC Cold | MPC Hot | ... | **Custody** | ✅ | ❌ | ✅ | ❌ |" - [undated, accessed 2026-10-29] primary: "Ether held in a native MPC wallet ("walletVersion": 6) requires consolidating to the base address ... Ether held in other wallet versions doesn't require manual consolidations, because those wallets use automatic forwarder smart contracts." - [2022-late (refers to TSS forwarders 'live in early 2023')] primary: "There are no changes to your existing wallets; to start using ETH TSS you will need to create a new wallet. ... If you prefer minimal administration, you may be still best-served by our ETH Multi-Sig base wallets." - [2024-06-24] primary: "BitGo now uses MPCv1 for EdDSA wallets and MPCv2 for ECDSA wallets. ... For simplicity, BitGo now refers to TSS wallets as MPC wallets" ### Copper (Copper.co, incl. ClearLoop) - **Class:** MPC/TSS (in-house) - **MPC share of ETH (best / low / high):** 95% / 85% / 100%; confidence: high - **Hot:** MPC (hot/warm vaults) - **Cold:** MPC (cold vaults, 2-of-3 shards) - **Notes:** Shards held by client, Copper and a third party (2-of-3). ClearLoop settles off-exchange from the same MPC vaults. - **Evidence:** - [2026-10-29 (retrieved; page undated)] primary: "Copper's three-shard MPC model and 2-of-3 signing quorum help protect assets without ever assembling a full private key." - [2024-11-20] primary: "Over 90% of balances in our vault custody, and over 95% of those in our omnibus accounts are held in cold storage. ... cold vault transactions are executed within minutes using our award-winning MPC custody solution." - [2020-04-06] primary: "we have recently embedded secure multi-party computation, or MPC technology, to materially enhance our key management and transaction security." ### Fireblocks (platform) - **Class:** MPC/TSS (vendor) - **MPC share of ETH (best / low / high):** 90% / 75% / 100%; confidence: medium - **Hot:** MPC-CMP (SGX-isolated key shares) - **Cold:** MPC with air-gapped shares (Cold Wallet) or HSM via KeyLink (customer choice) - **Notes:** KeyLink lets customers sign with their own HSM/KMS (secondary search summary of support.fireblocks.io Key Link overview); those wallets would be HSM, not MPC. Platform is self-custody software, so the ETH belongs to whoever uses it. - **Evidence:** - [2026-10-29 (retrieved; page undated)] primary: "Air-gapped MPC wallets with instant 24/7 access." ### Fireblocks Trust Company (NY) - **Class:** MPC/TSS (vendor) - **MPC share of ETH (best / low / high):** 95% / 80% / 100%; confidence: medium - **Hot:** MPC - **Cold:** MPC with key material on air-gapped offline devices - **Notes:** NYDFS limited-purpose trust charter 2024 (secondary). - **Evidence:** - [2026-10-29 (retrieved; page undated)] primary: "military-grade cold storage with offline transaction signing, key material stored on air-gapped, offline devices ... and MPC-based key management ensures private keys are never fully exposed." - [2025-10-08] primary: "Built on Fireblocks cold storage custody, layered with top physical security measures" ### Ceffu (ex-Binance Custody) - **Class:** MPC/TSS (in-house) - **MPC share of ETH (best / low / high):** 95% / 80% / 100%; confidence: medium - **Hot:** MPC/TSS (hardware-isolated) - **Cold:** Offline MPC/TSS, key shares on air-gapped FIPS 140-2 HSMs (Qualified Wallet) - **Notes:** MPC shares stored in HSMs still count as MPC (no key assembled). No post-2024 technical update found. - **Evidence:** - [2022-11-17] primary: "Our key management solution is based on the Threshold Signing Scheme (TSS) and key shares are generated on separate, air-gapped FIPS 140-2 compliant devices." - [2022-06-08] primary: "Secure and offline Multi-Party Computation (MPC) Key shares kept on air-gapped Hardware Security Modules (HSMs)" ### Cobo - **Class:** MPC/TSS (in-house) - **MPC share of ETH (best / low / high):** 85% / 60% / 100%; confidence: medium - **Hot:** MPC/TSS (TEE/SGX-protected shares) - **Cold:** MPC/TSS stated platform-wide; 95% cold - **Notes:** Quoted from Cobo's sandbox mirror of cobo.com/security (live URL 404'd). Not confirmed whether legacy fully custodial cold wallets also run on MPC; Cobo also sells Safe-based smart-contract wallets. - **Evidence:** - [2026-10-29 (retrieved; page undated)] primary: "Cobo uses advanced MPC cryptography with a Threshold Signature Scheme (TSS) ... A full private key never exists at any time" - [2026-10-29 (retrieved; page undated)] primary: "We use a hot-warm-cold private key storage system, with 95% of assets held in cold wallets." ### Komainu - **Class:** Hybrid - **MPC share of ETH (best / low / high):** 30% / 10% / 60%; confidence: low - **Hot:** MPC wallets (hot/warm) or HSM vault - **Cold:** HSM vault (Ledger-Vault-style: HSM + approvals on CC EAL5+ devices) or offline air-gapped MPC - **Notes:** No split given. The HSM option matches Ledger Vault (Ledger co-founded Komainu); the MPC vendor isn't named. Its largest ETH client (CoinShares ETPs) describes it as HSM-based, hence a low best guess. - **Evidence:** - [2026-10-29 (retrieved; page undated)] primary: "we offer two industry-leading options for key management: Hardware Security Modules (HSM) and Multi-Party Computation (MPC)." - [2026-10-29 (retrieved; page undated)] primary: "HSM ... Hosted in secure clusters of data centres ... with transaction authorisation certificates stored on CC EAL5+ air-gapped devices." - [2026-03-12] primary: "Komainu's market-leading hardware security modules (HSMs) and cryptographic security protocols provide an institutional-grade custody solution" ### Zodia Custody - **Class:** HSM-based single key with quorum/policy approval (not MPC) - **MPC share of ETH (best / low / high):** 5% / 0% / 20%; confidence: medium - **Hot:** HSM (warm, within seconds) - **Cold:** Air-gapped HSMs; master-key shards in vaults for recovery - **Notes:** The Dfns MPC is pitched for wider token coverage, so ETH probably stays on HSM. Master-key shards are a backup, so this is not MPC. - **Evidence:** - [2026-10-29 (retrieved; page undated)] primary: "Private keys stored in HSMs in secured data centres ... Client-controlled entitlement workflows and policies embedded in our HSMs" - [2026-10-29 (retrieved; page undated)] primary: "Cryptographic master keys are generated in an offline environment and are stored in HSMs. ... Zodia Custody stores shards of the master key in vaults" - [2024-12-05] primary: "introducing MPC infrastructure to complement our existing robust HSM tech stack." ### Hex Trust - **Class:** HSM-based single key with quorum/policy approval (not MPC) - **MPC share of ETH (best / low / high):** 2% / 0% / 10%; confidence: medium - **Hot:** HSM - **Cold:** Air-gapped HSM (FIPS 140-3 L3) - **Notes:** Secondary sources say IBM LinuxONE HSM. No sign of MPC for core custody. - **Evidence:** - [2026-10-29 (retrieved; page undated)] primary: "Seeds are generated inside the HSM using a compliant True Random Generator, and our HSMs are FIPS 140-3 Level 3 certified" - [2026-10-29 (retrieved; page undated)] primary: "At the core of its architecture is Hardware Security Module (HSM) technology, which securely manages and stores private keys in air-gapped , tamper-resistant environments." ### BNY (BNY Mellon Digital Asset Custody) - **Class:** MPC/TSS (vendor) - **MPC share of ETH (best / low / high):** 75% / 40% / 95%; confidence: low - **Hot:** Fireblocks-based - **Cold:** Fireblocks-based (MPC vs Fireblocks KeyLink/HSM not disclosed) - **Notes:** Live for BTC and ETH since Oct 2022; Chainalysis does compliance only and does not hold keys. No 2025-26 primary source on the key tech. A bank may well use Fireblocks KeyLink with its own HSMs, hence the wide range. Relevant because MSSE uses BNY plus Coinbase. - **Evidence:** - [2022-10] secondary: "The bank uses software developed with Fireblocks to store the keys required to access and transfer digital assets. (as summarised via search)" - [2022-10] secondary: "BNY Mellon will allow clients to hold Bitcoin and other cryptocurrencies in wallets supported by Fireblocks technology (search summary)" ### State Street - **Class:** HSM-based single key with quorum/policy approval (not MPC) - **MPC share of ETH (best / low / high):** 5% / 0% / 30%; confidence: low - **Hot:** Taurus-PROTECT (planned) - **Cold:** Taurus-PROTECT HSM (planned) - **Notes:** Taurus deal confirmed (Aug 2024). A 2026 launch was reported (Ledger Insights citing The Information, secondary), but I found no go-live confirmation. Likely holds negligible ETH today. - **Evidence:** - [2026-10-29 (retrieved; page undated)] primary: "Subject to receipt of applicable regulatory approvals, we will adopt Taurus' fully integrated custody, tokenization and node-management solutions" - [2026-10-29 (retrieved; page undated)] primary: "Taurus-PROTECT, which provides hot, warm and cold storage for digital assets" ### Gemini Custody (Gemini Trust) - **Class:** Hybrid - **MPC share of ETH (best / low / high):** 35% / 10% / 70%; confidence: low - **Hot:** MPC wallets plus legacy HSM hot wallets - **Cold:** Legacy: geographically distributed HSMs with multisig. New custody accounts: MPC - **Notes:** The 10-K lists 'MPC' and 'cold' wallets separately, so cold storage is the HSM system. No source says which one holds ETH. The 'multi-signature' in cold storage is likely native BTC multisig; for ETH it would mean an HSM single key or a contract wallet (unverified). The custody page says MPC is for (new) Custody accounts. Gemini is custodian for VanEck ETHV; its 10-K has no key-tech detail. - **Evidence:** - [2026-03-31] primary: "Our infrastructure features geographically distributed HSM supporting cold storage with advanced multi-signature technology, as well as MPC technology." - [2026-03-31] primary: "Our expanding number of regulated entities will rely on an increasing number of hot, MPC, and cold wallets" - [2026-10-29 (retrieved; page undated)] primary: "Transactions are signed using MPC without assembling the complete private key during storage or signing." - [2019-02-12] primary: "These keys exist on hardware security modules (HSMs) that meet or exceed FIPS 140-2 Level 3 U.S. government computer security standards." ### Paxos (Paxos Trust / national trust bank) - **Class:** HSM-based single key with quorum/policy approval (not MPC) - **MPC share of ETH (best / low / high):** 5% / 0% / 20%; confidence: medium - **Hot:** HSM-backed hot wallets - **Cold:** Air-gapped HSMs - **Notes:** Paxos owns Fordefi (an MPC wallet), which a secondary review says remains a separate architecture. Fiduciary custody is HSM. - **Evidence:** - [2026-10-29 (retrieved; page undated)] primary: "Keys are generated and held inside FIPS-grade HSMs, and plaintext keys never leave them. Tiered wallets available, with HSM-backed hot wallets for routine flows and cold wallets for long-term storage in air-gapped HSMs." ### Standard Custody & Trust (Ripple) - **Class:** Unknown - **MPC share of ETH (best / low / high):** 40% / 0% / 90%; confidence: low - **Hot:** Unknown - **Cold:** Unknown - **Notes:** Ripple acquired it (announced Feb 2024). It may migrate to Ripple Custody (HSM or MPC per vault). 'Distributed trust protocols' is ambiguous. Probably small ETH balance. - **Evidence:** - [2024-02-13] secondary: "novel blockchain technology that provides end-to-end encryption and distributed trust protocols for securing secret keys (search summary)" ### Taurus (Taurus-PROTECT) - **Class:** HSM-based single key with quorum/policy approval (not MPC) - **MPC share of ETH (best / low / high):** 10% / 0% / 30%; confidence: medium - **Hot:** HSM (FIPS 140-2 L3, Thales), MPC optional - **Cold:** Air-gapped HSM - **Notes:** The product page also lists 'State-of-the-art MPC algorithms', used for SaaS custody and to augment HSMs. Bank deployments (State Street, Deutsche Bank, CACEIS, Swissquote) are HSM-first. - **Evidence:** - [2026-10-29 (retrieved; page undated)] primary: "keys are generated, stored, and used inside FIPS-certified hardware security modules (HSMs) under the bank's exclusive control ... with air-gapped cold storage where regulation demands it." - [2021-02-24] primary: "What should a bank choose between HSM and MPC for digital asset custody?" ### Metaco / Ripple Custody - **Class:** Hybrid - **MPC share of ETH (best / low / high):** 20% / 0% / 50%; confidence: low - **Hot:** Per-vault choice: HSM or MPC - **Cold:** Per-vault choice: HSM or MPC - **Notes:** Ripple-managed MPC is 3-of-4 (2 Ripple + 2 customer nodes) per a secondary summary of the docs. The installed bank base (BBVA CH, Citi, SocGen-FORGE etc.) is mostly on-prem HSM (Thales/BlockSafe/Securosys). - **Evidence:** - [2026-10-29 (retrieved; page undated)] primary: "Each time you initialize and register a new vault, you must specify which key management model it will use: HSM or MPC." - [older doc v1.26] secondary: "multi-party computation (MPC) key management systems are currently only supported for selected customers (search summary)" ### Sygnum Bank - **Class:** Hybrid - **MPC share of ETH (best / low / high):** 30% / 10% / 60%; confidence: low - **Hot:** HSM + MPC (trading/vault wallets) - **Cold:** 'Sygnum Cryo' deep-cold, air-gapped (key tech not disclosed) - **Notes:** Multi-custody stack (secondary): Custodigit-Metaco, Securosys HSM and Taurus, all HSM-centric. MPC vendor not named. No split. - **Evidence:** - [2026-10-29 (retrieved; page undated)] primary: "Our security model combines FIPS-140.2 Level 3 hardware, Multi-Party Computation and Swiss-based Tier IV data centres." - [2026-06] primary: "clients can hold digital assets in different wallets, including trading, vault and cold wallets" ### Bitcoin Suisse - **Class:** Unknown - **MPC share of ETH (best / low / high):** 20% / 0% / 70%; confidence: low - **Hot:** Proprietary Bitcoin Suisse Vault - **Cold:** Proprietary Bitcoin Suisse Vault (EMP-shielded, keys in Switzerland) - **Notes:** No public statement of HSM, MPC or Shamir. ISAE 3402 Type 2 (PwC). - **Evidence:** - [2026-10-29 (retrieved; page undated)] primary: "At the core of both accounts we offer is the Bitcoin Suisse Vault, our robust, proprietary, institutional custody solution." ### Ledger Enterprise (Ledger Vault) - **Class:** HSM-based single key with quorum/policy approval (not MPC) - **MPC share of ETH (best / low / high):** 0% / 0% / 5%; confidence: high - **Hot:** HSM with governance enforced in HSM, m-of-n approvals on Ledger devices - **Cold:** Same HSM model - **Notes:** Not MPC. Ledger also sells a separate Safe-based 'Ledger Enterprise Multisig' (smart-contract multisig). - **Evidence:** - [2026-03-19] primary: "Ledger Enterprise initially protected governance objects using per-object monotonic counters inside HSMs to prevent replay attacks." ### Kraken custody (Kraken Financial) - **Class:** Hybrid - **MPC share of ETH (best / low / high):** 60% / 30% / 90%; confidence: low - **Hot:** MPC + HSM - **Cold:** MPC + HSM (split not disclosed) - **Notes:** Ambiguous: possibly MPC shares inside HSMs, which would make it MPC. No split published. - **Evidence:** - [2026-10-29 (retrieved; page undated)] primary: "cutting-edge MPC and HSM-based key storage and policy enforcement." - [2024-07-18] secondary: "Accounts come with MPC technology and HSMs for key storage and policy enforcements." ### Fidelity Digital Assets - **Class:** HSM-based single key with quorum/policy approval (not MPC) - **MPC share of ETH (best / low / high):** 0% / 0% / 10%; confidence: medium - **Hot:** HSM (certified, offline-capable) - **Cold:** Offline HSMs, geographically split authorization, 'deep cold storage' - **Notes:** The one-pager also says 'multi-signature for transfers'. For ETH that most likely means multi-party approval, not on-chain multisig (unverified). In-house; FDAS uses no third-party custodians (FCC 2022 press release, secondary). Custodian for US FETH; its 10-K has no key-tech detail. - **Evidence:** - [undated (FCC one-pager)] primary: "offline, certified Hardware Security Module (HSM) hardware for all online and offline private keys (quoted via search summary; PDF now 404)" - [2026-10-29 (retrieved; page undated)] secondary: "Private keys are each required to be accessed and authorized in varied geographic locations by separate teams of associates. (via search summary)" - [2026-10-28] primary: "The ether that the Ether Sub-Custodian holds for the Fidelity ETF is stored offline in cold storage." ## Custodian self-custody software ### Anchorage Porto (self-custody wallet) - **Class:** HSM-based single key with Shamir-style recovery (NOT MPC) - **MPC share of ETH (best / low / high):** 0% / 0% / 10%; confidence: high - **Hot:** HSM-backed; encrypted full private key exportable via 2-of-3 recovery shares - **Cold:** n/a - **Evidence:** - [undated, accessed 2026-10-29] primary: "Administrators can access and decrypt encrypted private keys. ... You require 2 out of 3 recovery shares to access your wallet." ## US spot ETH ETFs ### ETHA (iShares Ethereum Trust) - **Class:** Inherits Coinbase Custody Trust: key sharding with reconstruction per Grayscale filings (NOT MPC), possible partial MPC Vaults - **MPC share of ETH (best / low / high):** 15% / 0% / 60%; confidence: medium - **Hot:** n/a (ETF; >98% cold per prospectuses) - **Cold:** Inherits Coinbase Custody Trust: key sharding with reconstruction per Grayscale filings (NOT MPC), possible partial MPC Vaults - **Custodian(s):** Coinbase Custody Trust (primary), Anchorage Digital Bank (additional; 'no plans to move' ETH) - **ETH held:** 2695456 (as of 2026-06-30) - **Notes:** ETH held is the 2026-06-30 ending balance (2,695,456 ETH; fair value $4.29B). Derived later estimate: iShares site shows 140,533,284 shares and a basket of 904.84 ETH per 40,000 shares as of 2026-10-28, which implies about 3.18M ETH. The 40,000-share basket size is assumed from the prospectus convention. - **Evidence:** - [2026-08-06] primary (SEC filing): "Coinbase Custody Trust Company, LLC (the “Ether Custodian”) is responsible for safekeeping the ether owned by the Trust. Anchorage Digital Bank N.A. is the “Additional Ether Custodian” ... the Sponsor has no plans to move any of the Trust’s ether to the Additional Ether Custodian." ### ETHB (iShares Staked Ethereum Trust) - **Class:** Inherits Coinbase Custody Trust: key sharding with reconstruction per Grayscale filings (NOT MPC), possible partial MPC Vaults; 87% staked (validator withdrawal credentials controlled by custodian) - **MPC share of ETH (best / low / high):** 15% / 0% / 60%; confidence: medium - **Hot:** n/a (ETF; >98% cold per prospectuses) - **Cold:** Inherits Coinbase Custody Trust: key sharding with reconstruction per Grayscale filings (NOT MPC), possible partial MPC Vaults; 87% staked (validator withdrawal credentials controlled by custodian) - **Custodian(s):** Coinbase Custody Trust, Anchorage Digital Bank (additional) - **ETH held:** 288417 (as of 2026-06-30) - **Notes:** Launched Jan 2026. Most of its ETH sits in validators, not in custodian EOAs. - **Evidence:** - [2026-08-11] primary (SEC filing): "As of June 30, 2026, 250,585 ether (representing 86.9% of the position) are staked with third party counterparties." ### FETH (Fidelity Ethereum Fund) - **Class:** Fidelity Digital Assets (see custodian entry) + Anchorage (HSM) + BitGo (hybrid) - **MPC share of ETH (best / low / high):** 10% / 0% / 40%; confidence: low - **Hot:** n/a (ETF; >98% cold per prospectuses) - **Cold:** Fidelity Digital Assets (see custodian entry) + Anchorage (HSM) + BitGo (hybrid) - **Custodian(s):** Fidelity Digital Assets, N.A., Anchorage Digital Bank, BitGo Bank & Trust (added 2026 for staking) - **ETH held:** 476311 (as of 2026-06-30) - **Notes:** The 10-Q for Q2 2026 names only FDA. The 424B3 of 2026-08-21 lists Anchorage, BitGo and FDA as Custodians and says the fund will stake. Allocation among them is not disclosed. - **Evidence:** - [2026-08-06] primary (SEC filing): "Fidelity Digital Assets, N.A., an affiliate of the Sponsor, serves as the Trust’s ether custodian" - [2026-08-21] primary (FETH 424B3): "The Trust will custody its ether at Anchorage Digital Bank NA, BitGo Bank & Trust, N.A. (formerly BitGo Trust Company, Inc.), and Fidelity Digital Assets, N.A. ... Pursuant to its investment objective, the Sponsor will utilize the services of the Custodians to stake" ### ETHE (Grayscale Ethereum Staking ETF) - **Class:** Inherits Coinbase Custody Trust: key sharding with reconstruction per Grayscale filings (NOT MPC), possible partial MPC Vaults - **MPC share of ETH (best / low / high):** 15% / 0% / 60%; confidence: medium - **Hot:** n/a (ETF; >98% cold per prospectuses) - **Cold:** Inherits Coinbase Custody Trust: key sharding with reconstruction per Grayscale filings (NOT MPC), possible partial MPC Vaults - **Custodian(s):** Coinbase Custody Trust, Anchorage Digital Bank (additional, agreement 2025-08-08) - **ETH held:** 774998.51 (as of 2026-06-30) - **Notes:** Staking enabled. The 10-K text explicitly says key shards are combined to reconstitute the private key. - **Evidence:** - [2026-08-07] primary (SEC filing): "Coinbase, Inc. is the prime broker (the “Prime Broker”) of the Trust, and Coinbase Custody Trust Company, LLC is the custodian (the “Custodian”). ... Anchorage Digital Bank N.A. (the “Additional Custodian”) is an available alternative custodian of the Trust." - [2026-02-25] primary (Grayscale Ethereum Staking ETF FY2025 10-K describing Coinbase Custody Trust): "Once generated, private keys are encrypted, separated into “shards”, and then further encrypted. ... Multiple private key shards held by the Custodian must be combined to reconstitute the private key to sign any transaction in order to transfer the Trust’s Ether." ### ETH (Grayscale Ethereum Staking Mini ETF) - **Class:** Inherits Coinbase Custody Trust: key sharding with reconstruction per Grayscale filings (NOT MPC), possible partial MPC Vaults - **MPC share of ETH (best / low / high):** 15% / 0% / 60%; confidence: medium - **Hot:** n/a (ETF; >98% cold per prospectuses) - **Cold:** Inherits Coinbase Custody Trust: key sharding with reconstruction per Grayscale filings (NOT MPC), possible partial MPC Vaults - **Custodian(s):** Coinbase Custody Trust, Anchorage Digital Bank (additional) - **ETH held:** 854642.67 (as of 2026-06-30) - **Evidence:** - [2026-08-07] primary (SEC filing): "Coinbase Custody Trust Company, LLC is the custodian (the “Custodian”). ... Anchorage Digital Bank N.A. (the “Additional Custodian”) is an available alternative custodian of the Trust." - [2026-02-25] primary (Grayscale Ethereum Staking ETF FY2025 10-K describing Coinbase Custody Trust): "Once generated, private keys are encrypted, separated into “shards”, and then further encrypted. ... Multiple private key shards held by the Custodian must be combined to reconstitute the private key to sign any transaction in order to transfer the Trust’s Ether." ### ETHW (Bitwise Ethereum ETF) - **Class:** Inherits Coinbase Custody Trust: key sharding with reconstruction per Grayscale filings (NOT MPC), possible partial MPC Vaults - **MPC share of ETH (best / low / high):** 15% / 0% / 60%; confidence: medium - **Hot:** n/a (ETF; >98% cold per prospectuses) - **Cold:** Inherits Coinbase Custody Trust: key sharding with reconstruction per Grayscale filings (NOT MPC), possible partial MPC Vaults - **Custodian(s):** Coinbase Custody Trust - **ETH held:** 106742.1564 (as of 2026-06-30) - **Evidence:** - [2026-08-07] primary (SEC filing): "Coinbase Custody Trust Company, LLC serves as the Trust’s custodian for ether for which qualified custody is available (the “Ether Custodian”)." ### EZET (Franklin Ethereum ETF) - **Class:** Inherits Coinbase Custody Trust: key sharding with reconstruction per Grayscale filings (NOT MPC), possible partial MPC Vaults - **MPC share of ETH (best / low / high):** 15% / 0% / 60%; confidence: medium - **Hot:** n/a (ETF; >98% cold per prospectuses) - **Cold:** Inherits Coinbase Custody Trust: key sharding with reconstruction per Grayscale filings (NOT MPC), possible partial MPC Vaults - **Custodian(s):** Coinbase Custody Trust - **ETH held:** 20464.3242 (as of 2026-06-30) - **Evidence:** - [2026-08-14] primary (SEC filing): "The Ether Custodian is Coinbase Custody Trust Company, LLC (“Coinbase Custody”)." ### QETH (Invesco Galaxy Ethereum ETF) - **Class:** Inherits Coinbase Custody Trust: key sharding with reconstruction per Grayscale filings (NOT MPC), possible partial MPC Vaults - **MPC share of ETH (best / low / high):** 15% / 0% / 60%; confidence: medium - **Hot:** n/a (ETF; >98% cold per prospectuses) - **Cold:** Inherits Coinbase Custody Trust: key sharding with reconstruction per Grayscale filings (NOT MPC), possible partial MPC Vaults - **Custodian(s):** Coinbase Custody Trust - **ETH held:** 9782 (as of 2026-06-30) - **Evidence:** - [2026-08-07] primary (SEC filing): "Coinbase Custody Trust Company, LLC (the “Ethereum Custodian”) holds all of the Trust’s ether on the Trust’s behalf as Ethereum Custodian." ### ETHV (VanEck Ethereum ETF) - **Class:** Gemini (HSM cold storage, some MPC) + Coinbase Custody - **MPC share of ETH (best / low / high):** 15% / 0% / 50%; confidence: low - **Hot:** n/a (ETF; >98% cold per prospectuses) - **Cold:** Gemini (HSM cold storage, some MPC) + Coinbase Custody - **Custodian(s):** Gemini Trust Company (primary ETH Custodian), Coinbase Custody Trust (additional) - **ETH held:** 48971.93 (as of 2026-06-30) - **Evidence:** - [2026-08-13] primary (SEC filing): "Deposits of ETH are held by Gemini Trust Company, LLC (the “ETH Custodian”) and at Coinbase Custody Trust Company, LLC (the “Additional ETH Custodian” ...)" ### TETH (21Shares Ethereum Staking ETF; formerly CETH) - **Class:** Mixed: Coinbase (sharded key) + BitGo (multisig/MPC) + Anchorage (HSM) - **MPC share of ETH (best / low / high):** 15% / 0% / 50%; confidence: low - **Hot:** n/a (ETF; >98% cold per prospectuses) - **Cold:** Mixed: Coinbase (sharded key) + BitGo (multisig/MPC) + Anchorage (HSM) - **Custodian(s):** Coinbase Custody Trust, BitGo Bank & Trust, BitGo New York Trust, Anchorage Digital Bank - **ETH held:** 8185.4684 (as of 2026-06-30) - **Notes:** 86.42% of ETH staked as of 2026-06-30. - **Evidence:** - [2026-08-14] primary (SEC filing): "Coinbase Custody Trust Company, LLC (“Coinbase”), BitGo Bank & Trust, N.A. (“BitGo”), BitGo New York Trust Company, LLC (“BitGo New York”), and Anchorage Digital Bank N.A. ... are the custodians for the Trust and hold all of the Trust’s ether" ### MSSE (Morgan Stanley Ethereum Trust) - **Class:** BNY (see custodian entry) + Coinbase Custody; prospectus lists 'MPC, HSMs and CDS' generically - **MPC share of ETH (best / low / high):** 30% / 0% / 80%; confidence: low - **Hot:** n/a (ETF; >98% cold per prospectuses) - **Cold:** BNY (see custodian entry) + Coinbase Custody; prospectus lists 'MPC, HSMs and CDS' generically - **Custodian(s):** The Bank of New York Mellon (BNY), Coinbase Custody Trust - **ETH held:** None (as of launched 2026-07 (no 10-Q yet)) - **Notes:** Allocation between BNY and Coinbase is at the sponsor's discretion. ETH holdings not yet reported. - **Evidence:** - [2026-07-23] primary (SEC filing): "The Bank of New York Mellon (“BNY”) and Coinbase Custody Trust Company, LLC (the “Coinbase Custodian” and together with BNY, the “Ether Custodians”) have each been appointed as ether custodians for the Trust." - [2026-07-23] primary (Morgan Stanley Ethereum Trust 424B3; custodians = BNY and Coinbase Custody; generic language not attributed to either custodian; identical boilerplate appears in 21Shares prospectuses since May 2025): "Similarly secure technology used by the Ether Custodians includes a combination of Multi-Party Computation (“MPC”), Hardware Security Modules (“HSMs”), and Cross-Domain Security (“CDS”) to safeguard digital assets." ## Non-US ETH ETPs ### 21Shares Ethereum Staking ETP (AETH) - **Class:** Hybrid - **MPC share of ETH (best / low / high):** 10% / 0% / 40%; confidence: medium - **Hot:** n/a (ETP) - **Cold:** per custodian - **Custodian(s):** BitGo, Coinbase Custody Trust Company, LLC, Zodia Custody Limited - **ETH held:** 121456.27 (as of 2026-10-28) - **Notes:** No per-custodian split. Zodia is HSM. Coinbase and BitGo classes come from the parent's own research. The MPC share is driven by BitGo (TSS vs WalletSimple). - **Evidence:** - [2026-10-29 (retrieved; page undated)] primary: "Custody BitGo, Coinbase Custody Trust Company, LLC, Zodia Custody Limited" - [2026-10-28] primary: "total_units_outstanding: 11015000 ... coin_entitlement_per_share: 0.011026443251 ... valuation_date: 2026-10-28" ### 21Shares Ethereum Core Staking ETP (ETHC) - **Class:** Hybrid - **MPC share of ETH (best / low / high):** 10% / 0% / 50%; confidence: medium - **Hot:** n/a (ETP) - **Cold:** per custodian - **Custodian(s):** BitGo, Coinbase Custody Trust Company, LLC - **ETH held:** 46754.63 (as of 2026-10-28) - **Notes:** Other 21Shares basket ETPs hold small ETH amounts (not computed). - **Evidence:** - [2026-10-28] primary: "active_custodian_agents: BitGo, Coinbase Custody Trust Company, LLC" ### CoinShares Ethereum Staking ETP (ETHE, ex-CETH; GB00BLD4ZM24) - **Class:** Hybrid - **MPC share of ETH (best / low / high):** 15% / 0% / 40%; confidence: low - **Hot:** n/a (ETP) - **Cold:** per custodian - **Custodian(s):** Komainu (Jersey), Zodia Custody - **ETH held:** 164372 (as of 2026-10-27/28) - **Notes:** Komainu is described as HSM for this product, and Zodia is also named, so it is likely mostly HSM. - **Evidence:** - [2026-03-12] primary: "Assets are securely held with Komainu ... Komainu's market-leading hardware security modules (HSMs) and cryptographic security protocols" - [2026-10-28] primary: "aum 383277488; product 70.96; ETP_ENTITLEMENT 2026-10-27: 0.03043182" ### CoinShares XBT Provider Ether Tracker One (SEK) / Ether Tracker Euro (COINETH, COINETHE) - **Class:** Unknown - **MPC share of ETH (best / low / high):** 15% / 0% / 60%; confidence: low - **Hot:** n/a (ETP) - **Cold:** per custodian - **Custodian(s):** Hedge assets held by CoinShares (custodian not stated per product) - **ETH held:** 207955 (as of 2026-10-28) - **Notes:** Unsecured ETNs. CoinShares' hedge ETH sits with its custodians (Komainu, others). Treat as an ETH holding of unknown custody. - **Evidence:** - [2026-10-28] primary: "Ether Tracker One - SEK ... aum US$ 185944254.02; Ether Tracker Euro - EUR ... aum US$ 299073928.29" ### Bitwise Physical Ethereum ETP (ZETH) - **Class:** Hybrid - **MPC share of ETH (best / low / high):** 10% / 0% / 40%; confidence: medium - **Hot:** n/a (ETP) - **Cold:** per custodian - **Custodian(s):** BitGo Trust, Coinbase Custody Trust, Zodia Custody - **ETH held:** 40106.64 (as of 2026-10-22) - **Notes:** No per-product custodian split. - **Evidence:** - [2026-10-22] primary: "ZETH ... 4,360,798 ... ETH 0.00918500 ... 40,053.9109 ... 40,106.6442" - [2026-10-29 (retrieved; page undated)] primary: "Bitwise only partners with leading providers of digital asset custody BitGo ... Coinbase Custody ... Zodia" ### Bitwise Ethereum Staking ETP (ET32) - **Class:** Hybrid - **MPC share of ETH (best / low / high):** 10% / 0% / 40%; confidence: medium - **Hot:** n/a (ETP) - **Cold:** per custodian - **Custodian(s):** BitGo Trust, Coinbase Custody Trust, Zodia Custody - **ETH held:** 76244.34 (as of 2026-10-22) - **Notes:** The Bitwise MSCI DA20 basket holds about 2,656 ETH more. - **Evidence:** - [2026-10-22] primary: "ET32 ... 36,802,024 ... ETH 0.00207085 ... 76,211.5103 ... 76,244.3384" ### VanEck Ethereum ETN (VETH, DE000A3GPSP7) - **Class:** Unknown - **MPC share of ETH (best / low / high):** 20% / 0% / 80%; confidence: low - **Hot:** n/a (ETP) - **Cold:** per custodian - **Custodian(s):** Unknown (page says only 'regulated crypto custodian') - **ETH held:** 70118 (as of 2026-10-28) - **Notes:** Couldn't fetch the custodian (factsheet/prospectus download redirected). Historically Bank Frick (unverified). - **Evidence:** - [2026-10-28] primary: "Total Net Assets $ 163.54 million as of 28 Oct 2026" ### WisdomTree Physical Ethereum - **Class:** Unknown - **MPC share of ETH (best / low / high):** 15% / 0% / 60%; confidence: low - **Hot:** n/a (ETP) - **Cold:** per custodian - **Custodian(s):** Unknown (site 403 behind Cloudflare) - **ETH held:** None (as of None) - **Notes:** Not resolved. From memory (unverified): Coinbase Custody and Zodia. - **Evidence:** ### iShares Ethereum ETP (Europe) - **Class:** Unknown - **MPC share of ETH (best / low / high):** 10% / 0% / 60%; confidence: low - **Hot:** n/a (ETP) - **Cold:** per custodian - **Custodian(s):** Unknown - **ETH held:** None (as of None) - **Notes:** Not resolved; web-search budget exhausted. - **Evidence:** ### Purpose Ether ETF (ETHH, Canada) - **Class:** Hybrid - **MPC share of ETH (best / low / high):** 10% / 0% / 50%; confidence: low - **Hot:** n/a (ETP) - **Cold:** per custodian - **Custodian(s):** Three sub-custodians incl. Anchorage Digital Bank (others not verified; likely Gemini Trust and Coinbase Custody) - **ETH held:** 119520.52 (as of 2026-10-28) - **Notes:** Gemini is hybrid (see above). Anchorage and Coinbase classes come from the parent's own research. - **Evidence:** - [2026-10-28] primary: "FUND AUM CAD $398.79M NUMBER OF ETHER 119520.52149800002 ETH ( 2026-10-28 )" - [2026] primary: "Purpose Investments Becomes First Digital Asset ETF Manager in Canada to Operate a Three-Sub-Custodian Model, Adding Anchorage Digital Bank" ### Fidelity Advantage Ether ETF (FETH, Canada) - **Class:** HSM-based single key with quorum/policy approval (not MPC) - **MPC share of ETH (best / low / high):** 0% / 0% / 10%; confidence: medium - **Hot:** n/a (ETP) - **Cold:** per custodian - **Custodian(s):** Fidelity Clearing Canada (custodian), Fidelity Digital Asset Services (sub-custodian) - **ETH held:** 25019.07 (as of 2026-10-28) - **Notes:** At least 98% in cold wallets. - **Evidence:** - [2026-10-28] primary: "Number of ether in fund ... 25019.0741 28-Oct-2026 ... The ether that the Ether Sub-Custodian holds for the Fidelity ETF is stored offline in cold storage." ### CI Galaxy Ethereum ETF (Canada) - **Class:** Unknown - **MPC share of ETH (best / low / high):** 10% / 0% / 60%; confidence: low - **Hot:** n/a (ETP) - **Cold:** per custodian - **Custodian(s):** Unknown - **ETH held:** None (as of None) - **Notes:** Not resolved. - **Evidence:** ### 3iQ Ether Staking ETF (ETHQ, Canada) - **Class:** Unknown - **MPC share of ETH (best / low / high):** 10% / 0% / 60%; confidence: low - **Hot:** n/a (ETP) - **Cold:** per custodian - **Custodian(s):** Unknown (product page 404) - **ETH held:** None (as of None) - **Notes:** Not resolved. From memory (unverified): Tetra Trust and Coinbase. - **Evidence:** ### ChinaAMC Ethereum ETF (HK) - **Class:** Unknown - **MPC share of ETH (best / low / high):** 30% / 0% / 90%; confidence: low - **Hot:** n/a (ETP) - **Cold:** per custodian - **Custodian(s):** Unknown (page JS-only) - **ETH held:** None (as of None) - **Notes:** Not resolved. From memory (unverified): OSL Digital Securities. OSL custody tech not researched. - **Evidence:** ### Harvest Ethereum ETF (HK) - **Class:** Unknown - **MPC share of ETH (best / low / high):** 30% / 0% / 90%; confidence: low - **Hot:** n/a (ETP) - **Cold:** per custodian - **Custodian(s):** Unknown - **ETH held:** None (as of None) - **Notes:** Not resolved. From memory (unverified): OSL Digital Securities. - **Evidence:** ### Bosera HashKey Ethereum ETF (HK) - **Class:** Unknown - **MPC share of ETH (best / low / high):** 30% / 0% / 90%; confidence: low - **Hot:** n/a (ETP) - **Cold:** per custodian - **Custodian(s):** Unknown - **ETH held:** None (as of None) - **Notes:** Not resolved. From memory (unverified): HashKey Exchange (Hash Blockchain Ltd). - **Evidence:**