Wrapped Bitcoin (WBTC) is the dominant Bitcoin-backed token in DeFi, representing a bridge between Bitcoin's store-of-value properties and Ethereum-based smart-contract ecosystems. As of May 2026, WBTC commands a $9.0 billion market cap and 118,022 BTC in circulating supply, maintaining 81% market share of the wrapped Bitcoin category despite intensifying competitive pressure from alternatives like Coinbase's cbBTC and decentralized solutions like tBTC.