A trader bought $208,000 worth of Gains Network (GNS) tokens less than 30 minutes before the token was listed on Binance, making a profit of $106,000, according to blockchain sleuth Lookonchain.

GNS, the token that underlies Gains Network's decentralized exchange, jumped to $12.01 from $7.92 immediately following the listing. The trader bought the tokens on decentralized exchange aggregator 1Inch before selling them on the same venue after the price had surged.

Last month, Conor Grogan, head of product at rival exchange Coinbase, said in a Twitter thread that what appeared to be front-running had been occurring on Binance for more than 18 months.

"If this is front-running, there could be a few reasons for it," he wrote. "Insider MNPI, most likely from a rogue employee connected to the listings team who would have details on new asset announcements, or a trader who found some sort of API or staging/test trade exchange leak."

MNPI is an abbreviation for material non-public information while API describes an application interface that allows one program to retrieve data from another. Trading firms often use APIs to trade across multiple exchanges.

Binance Chief Strategy Officer Patrick Hillmann responded by saying company policy restricts Binance employees from trading over short periods, with a 90-day lock being imposed on token sales. The policy has been in place since 2021, he said.

Binance did not immediately respond to a request for comment.

UPDATE (Feb. 17, 2023, 12:57 UTC): Adds description of MNPI and API in fifth paragraph.