Bitcoin
Bitcoin is the first and largest cryptocurrency, a decentralized digital currency with a fixed maximum supply of 21 million coins, recorded on a public blockchain.
Bitcoin was introduced in a 2008 white paper by the pseudonymous Satoshi Nakamoto, and its network launched in January 2009. It allows people to send value directly to one another over the internet without a bank, with transactions confirmed by a global network of miners.
Miners use computing power to solve cryptographic puzzles in a process called proof of work. The winner adds a new block of transactions to the blockchain about every ten minutes and receives newly created bitcoin as a reward. That reward is cut in half roughly every four years in an event known as the halving, and the total supply is capped at 21 million.
Supporters see bitcoin as digital gold, a scarce store of value outside government control. Critics point to its high volatility, energy use and limited use for everyday payments. Its price has experienced multiple booms and crashes.
Bitcoin is divisible into 100 million units called satoshis, so investors can buy small fractions. US investors can hold it directly or through spot bitcoin ETFs approved by the SEC in January 2024.