These services offer collaborative custody of your Bitcoin:
Unchained Capital
Unchained Capital offers various self-custody options for Bitcoin holders. They offer “vaults” which are a form of self-custody where users hold the keys to their Bitcoin, and Unchained acts as a security partner. The vaults are designed to eliminate a single points of failure.
Swan
Swan recently introduced a “collaborative custody” service using Blockstream’s hardware wallet, Jade.
Like Unchained, users control their Bitcoin via a 2-of-3 multisig setup. The customer securely holds two keys offline with two Jade devices,. Swan has a third key to assist with recovery if needed.
Nunchuk
Nunchuk is another collaborative custody platform. You can lose one or more keys and still be able to access your funds. Spending requires more than one key.
