UNUS SED LEO is a utility token that’s used across the iFinex ecosystem. The unusual name is based on a Latin citation from one of Aesop’s fables. The cryptocurrency allows Bitfinex users to save money on trading fees. The extent of the discount depends on how much LEO that the customer has in their account — and the savings on offer are spread across three tiers. There are fluctuations depending on whether a trading pair is crypto-to-crypto or crypto-to stablecoin. UNUS SED LEO launched in May 2019 — and unlike many other cryptocurrencies out there it is not designed to exist forever.