Three independent institutions protect your bitcoin, and you never hold a key yourself. For individual and IRA vaults, those institutions are Onramp, BitGo, and CoinCover.
For business vaults, they're Onramp, Tetra Trust, and CoinCover.
No one of them can lose your bitcoin, move it, or use it, and nothing moves without your permission. Multi-institution custody works like a bank vault that needs two keyholders to open: it takes two of the three institutions to move your bitcoin.
Each institution secures its key offline, never on a consumer device, in a 2-of-3 multisig. You never hold a key, a seed phrase, or a hardware wallet.