However, some have pointed out that issues with Coinbase's API leaked information about which coins were about to be listed, which could have enabled people to obtain the information allowing them to make such trades without an insider connection.
Researchers estimate that an insider trader profited from 10–25% of new crypto listings at Coinbase
It's no secret that insider trading has happened at Coinbase, with the U.S. Attorney's Office of the Southern District of New York filing charges in July against three individuals, including a former Coinbase product manager, for their involvement in a scheme to trade on non-public information. However, researchers at the University of Technology Sydney have published a study showing that a group of four connected wallets appeared to trade based on the knowledge of tokens that were about to be listed by Coinbase. The trader(s) took positions in the coins ahead of the announcements, then sold the tokens soon after the listing announcement when they increased in value based on the news. The wallets involved in the trading scheme made a total profit of around 1,003 ETH ($1.88 million), which the researchers note is a conservative estimate of insider profits at Coinbase.