It was Jamie Dimon’s steady hand on the tiller of JPMorgan Chase, as he navigated the nation’s largest bank through a financial crisis that destroyed several of his peers and won him near legendary status. But now that reputation is taking a hit, as he struggles to bring JPMorgan through the rough seas of a massive derivatives trading loss.

In May, the bank announced that it had incurred at least $2 billion in losses in attempts to hedge against credit risk, a sum that soon ballooned to $3 billion and could go higher still. Now many are asking how this could have happened so soon after several banks were slain by similar transactions.