AMPL is an ERC-20 token that functions as a decentralised unit of account within the Ampleforth protocol. Unlike fixed-supply tokens, AMPL uses an elastic supply mechanism to adjust the quantity of tokens in user wallets based on market demand. The token targets the value of a 2019 USD adjusted for inflation, with supply rebasing daily to help stabilise its long-run average price. This approach allows AMPL to maintain purchasing power over time without relying on collateral, central banks, or market makers. AMPL is used in decentralised lending, borrowing, and derivative creation, and can serve as collateral for decentralised stablecoins. While users experience supply volatility, contracts denominated in AMPL aim to remain predictable in value over time. The token is governed through the FORTH DAO.