f(x) is an ETH-based leverage protocol designed to address the cryptocurrency sector's demand for stable assets while reducing risks associated with centralization and capital efficiency. The protocol introduces a new concept known as "floating stablecoins" or fETH. Unlike traditional stablecoins, fETH is not pegged to a fixed value; instead, it tracks a small portion of the price fluctuations of native Ethereum (ETH). In addition, a supplementary asset called xETH is created to serve as a zero-cost leveraged long position in ETH. xETH absorbs the majority of ETH's price volatility, which helps stabilize the value of fETH.