$BTC Bitcoin (BTC) is the world’s first and most prominent cryptocurrency, introduced in 2009 by the pseudonymous Satoshi Nakamoto. It functions as decentralized digital money without a central bank or single administrator. Transactions are recorded on a secure, immutable blockchain. Bitcoin’s fixed supply of 21 million coins makes it an attractive hedge against inflation. As of 2025, BTC remains the largest cryptocurrency by market cap and is increasingly viewed as "digital gold." Institutional adoption, regulatory developments, and macroeconomic conditions continue to influence its price.