Wrapped BTC (WBTC) is a Bitcoin‑backed ERC‑20 minted by BitGo under a multi‑sig controlled by merchants and custodians. Each token is 1:1 redeemable for BTC, with reserves published every 24 hours and verifiable on chain. WBTC accounts for more than 70 % of tokenised bitcoin on Ethereum and serves as core collateral for Aave, Maker and Compound.