January 27, 2020 Fidelity overview of the omnibus model of asset custody.

The omnibus model is a prominent method of custodianship that combines clients’ assets and spreads them across multiple private and public key pair groups. This is in contrast to the segregated model, in which separate keys are maintained for every depositor. The omnibus model draws from the traditional financial world, specifically the Depository Trust Company, which is the world’s largest securities depository. For cryptoassets, this approach presents advantages such as better risk management through flexible key generation structures, liquidity by minimizing hot wallet balances, privacy, and reduced transaction fees.