BlackRock adds new Bitcoin custodian Anchorage Digital alongside Coinbase

BlackRock has expanded the custodial structure of its iShares Bitcoin Trust (IBIT), formalizing Anchorage Digital Bank N.A. as an additional Bitcoin custodian through a new Master Custody Service Agreement.

The development, disclosed in a Form 8-K filing dated April 7, 2025, introduces a secondary custodian while Coinbase continues to serve as the primary holder of the trust’s Bitcoin reserves.

Dual-Custodian Model Enhances Redundancy

The agreement establishes a dual-custodian model between BlackRock Fund Advisors, the trust’s administrative trustee, and Anchorage, a federally chartered digital asset bank.

There will not be an immediate transfer of assets. Instead, Anchorage will remain on standby as a qualified custodian to support the trust’s risk mitigation protocols.

Per the filing, Anchorage is required to utilize cold storage solutions for all private keys, maintain insurance coverage, and comply with provisions that address blockchain forks and indemnification responsibilities.

This move is consistent with BlackRock’s positioning of the IBIT ETF as a scalable and resilient product. The presence of a second custodian does not alter the trust’s investment strategy or its underlying operational mechanics, but it introduces greater structural flexibility.

Institutional Signal Amid Growing Asset Base

The strategic addition of Anchorage may reflect BlackRock’s expectations of increased Bitcoin holdings within IBIT and the need for operational redundancy.

Since its launch, IBIT has ranked among the top spot Bitcoin ETFs (and also ETFs overall) in terms of inflows, making risk diversification a logical extension of its custodial setup.

Having Anchorage in reserve bolsters resilience against potential disruptions in custody services, whether operational, regulatory, or technical. The selection of Anchorage, a bank regulated by the Office of the Comptroller of the Currency (OCC), further emphasizes a preference for institutions that meet federal banking standards.

Anchorage is among the few crypto-native firms to receive a national trust bank charter, a factor that could enhance the trust’s compliance posture in a regulatory environment still shaping its treatment of digital asset custodians.

Status Quo Maintained for Now

While the addition of Anchorage introduces new operational options, no assets have yet been transferred. Coinbase remains fully responsible for current custodial functions, and the trust’s overall structure, fee arrangement, and investment objectives remain unchanged.

The agreement’s role appears preparatory, building a custodial contingency plan without altering day-to-day fund administration.

By preparing a framework for multi-custodian support, BlackRock signals a methodical approach to operational risk while positioning IBIT for long-term institutional participation. This development aligns with much of the community’s desire for diversification of custodial relationships as a baseline standard for fiduciary responsibility.