Initial Exchange Offerings (IEOs) are fundraising events where the crypto project raises money via a trading platform. This directly contradicts ICOs (Initial Coin Offerings) where the project itself raises funds using its own website.
IEOs gained popularity after China banned ICOs at the end of 2017. With IEOs, the crypto exchange is responsible for fundraising on behalf of the company while launching new tokens.
Startups are often charged a fee along with certain proportions of the sold tokens while raising funds via the exchange. Once the IEO is completed, the token gets listed on the exchange, allowing the startup to gain more exposure.