An Initial Exchange Offering (IEO) is a fundraising event held directly on cryptocurrency exchanges by cryptocurrency projects. During an IEO, the exchange serves as a facilitator, hosting the token sale on its platform and performing due diligence on investors' behalf.
An Initial Coin Offering (ICO) is a way of generating cash utilized by cryptocurrency entrepreneurs. During an ICO, a company sells its own digital tokens or coins in exchange for established cryptocurrencies such as Bitcoin or Ethereum, as well as fiat currency.