Matt Zames, chief operating officer at JP Morgan is stepping down from the giant bank, according to an internal memo obtained by MarketWatch.

Zames, often described as an heir apparent to CEO Jamie Dimon, had worked at the bank for some 13 years and had held some of the bank's most important roles, including serving as chief investment officer in the wake of the so-called London Whale scandal, which saddled the bank with an embarrassing loss and dented its risk-management reputation.