Onramp CEO Urges Three Checks for Corporate Bitcoin Custody

Onramp CEO Michael Tanguma is urging companies that hold Bitcoin (BTC) to examine three custody questions: who controls the assets, who approves transfers and whether holdings can be checked independently.

Tanguma argues that an account balance does not answer all three. Proof-of-reserves snapshots can show assets at a point in time, but they do not explain who can authorize a future withdrawal. Dividing signing authority among institutions addresses control over transfers; a corporate client also needs a way to verify its own holdings.

Tanguma has accused Coinbase of concealing Bitcoin assets.

Tanguma advocates a multi-signature custody model in which independent institutions create and hold separate keys. The company retains legal ownership, while no single custodian can move its Bitcoin alone. Named users, withdrawal approvals and an audit trail would govern transfer requests.

Companies also need a way to check their holdings directly. That gives them a way to examine the assets held under a custody arrangement without relying solely on an account balance. The ability to confirm holdings is separate from a company’s rules about who may request and approve a withdrawal.

Audits, trust charters and SOC reports assess a custodian’s records and processes. Those reviews alone do not establish a corporate client’s transfer approval rules or let it independently check its holdings.

Corporate controls are a concern beyond Bitcoin custody. In a second-quarter 2025 survey of 200 chief financial officers, 42% cited accounting and controls complexity as a concern about cryptocurrency investment, second only to price volatility. The survey covered cryptocurrency broadly, rather than Bitcoin alone.