Wrapped Bitcoin (WBTC) is an ERC-20 token that is backed one to one with Bitcoin held in custody by the BitGo trust. When Bitcoin is wrapped, it allows it to be used in the Decentralised Finance (DeFi) ecosystem. This enables the use of Bitcoin as collateral in a plethora of different DeFi applications such as Uniswap, Sushiswap, Aave, Compound, MakerDAO, Balancer and many more. This brings more liquidity into the DeFi ecosystem.