Are Unchained Capital keys held by a third party to custody bitcoin assets?

No. Unchained custodies our own keys.

How we custody keys:

Our multisig vaults utilize Unchained as a backup key signer. These backup keys are protected by our in-house security model and are geographically distributed. While we can't reveal specific details, know that a third party never holds our keys.

Our partnership with Kingdom Trust:

Unchained has a strategic partnership with Kingdom Trust, a subsidiary of Choice. Kingdom Trust is a trusted third party for our loans and multi-institution vaults. On your loan or multi-institution vault, your key is highlighted in green, while the Unchained and Kingdom Trust keys are greyed out and show the company logos.

Multi-institution-Kingdom-Trust

For more information about Kingdom Trust, see our announcement on the Unchained blog.