JPMorgan Chase & Co. on Tuesday named Jennifer Piepszak its new chief operating officer, but the company’s four major department heads remain more likely successors to Chief Executive Jamie Dimon to head up the largest U.

Doug Petno, JPMorgan’s co-head of global banking, will succeed Piepszak as co-CEO of JPMorgan’s commercial and investment bank, alongside Troy Rohrbaugh. The move appears to make Piepszak the front-runner to succeed Jamie Dimon as CEO and potentially become the first woman to lead the nation’s largest bank.

The long-time senior executive takes over the operations role from Daniel Pinto, who will retire at the end of next year.