An unnamed official at the Financial Supervisory Service (FSS) told Reuters that Steve Lee, CEO of the unit, has been investigated over trades which are thought to have occurred during 2009.
Local press in South Korea first reported the news of the investigation, with Money Today claiming that Mr Lee was recently quizzed by a team at Seoul Central Prosecutors Office over trades relating to KCC, a firm dealing in construction materials.
He is thought to have denied the allegations and claimed that he has not been investigated by the FSS.
However, Mr Lee stated that a relative had been questioned over transactions involving KCC stocks.
The anonymous source of the FSS told Reuters: âWe probed JPMorgan and its chief over unfair trading and referred the issue to prosecutors.â
According to the Financial Times, the CEO has worked with JPMorganâs South Korean unit since 1995.
By Jim Ottewill