Custody and key-management requirements when the treasury runs an active overlay

A digital-asset custody agreement negotiated for a buy-and-hold reserve programme and one adequate for an active overlay programme are not the same document. Most treasuries negotiate the first and run the second, discovering the gaps when a margin call requires a collateral movement the custodian cannot process within the required window.

The segregation requirement

An overlay programme that posts BTC as collateral against derivative positions must move specific coin from the custody arrangement to a counterparty-controlled segregated address. This requires the custody agreement to permit directed transfers, specify the authentication process for a transfer instruction, and provide timely execution against a stated service level. Standard custody agreements written for passive holdings are often silent on all three.

The segregation must also be bankruptcy-remote. Collateral posted to a dealer-controlled address that is not segregated from the dealer's general assets creates counterparty credit exposure on the posted collateral. The ISDA CSA should specify segregated treatment; the custody agreement should be consistent with it. Where they conflict, the CSA governs the obligation but the custody agreement governs the mechanics, and the gap between them is where loss occurs.

Collateral movement protocols

A margin call in a derivatives programme is time-sensitive. The call arrives; the treasury has a defined cure period (typically one to two business days under standard ISDA); if the call is not met, the dealer may close the position. A custody arrangement that requires a multi-signature ceremony, a manual approval workflow involving personnel not available on the cure timeline, or a processing queue that does not clear within the cure window will fail to meet the call.

The custody protocol for overlay programmes should specify: who is authorised to initiate a collateral transfer, what authentication is required, what the expected execution time is, and the escalation path if the primary process is unavailable. These protocols should be tested before the programme starts, not when the first margin call arrives.

The audit trail

Every collateral movement in an overlay programme is a transaction the auditor will want to trace from the policy authorisation through the custody record through the counterparty's acknowledgment. A custody system that records movements with sufficient metadata (timestamp, quantity, counterparty, authorising signatory) supports this trace. A system that logs only the transaction hash against the blockchain does not. The audit trail requirement for the custody system should be specified in writing, verified against the custodian's actual capability, and tested against a sample of historical transactions before programme inception.

What to negotiate before the first trade

Three additions to a standard custody agreement that an overlay programme requires: a permitted-transfer clause that explicitly covers derivative collateral movements; a response-time service level that matches the ISDA cure-period requirements; and an audit-rights clause that allows the treasury's auditors to confirm custody records directly with the custodian. None of these are unusual requests. All of them should be in the document before the first trade, not appended as an amendment when the need arises.