Gearbox is a composable leverage protocol that improves capital efficiency within DeFi. It introduces a novel DeFi primitive called Credit Accounts, which are isolated smart contracts with predefined, whitelisted parameters such as liquidation thresholds and approved tokens. Credit Accounts contain both user funds and borrowed margin funds, and they can be deployed on any DeFi protocol. They are non-custodial, so users never give up ownership of their assets. All operations go through the Credit Accounts, giving users an easy way to move across the DeFi ecosystem and leverage-interact with any protocol they choose.