By Matthew Goldstein and Jennifer Ablan

Jamie Dimon’s coat of teflon is wearing well, even as the criminal and regulatory investigation into the London Whale trading scandal deepens.

Shares of JPMorgan Chase, which plunged more than 20 percent in the days after the bank revealed in May that the trading losses were much worse than previously believed, have rallied back. The stock is now trading around $38.66 a share. On May 10, when the bank disclosed after the bell that it had lost at least $2 billion on derivatives bets made by a group of London-based traders, the stock closed at around $40.

When Dimon was called before Congress to testify on the trading scandal in June, he was generally treated like the king of Wall Street by congressman and senators. At the time, bank’s internal probe had not yet found evidence that the three traders may have tried to hide their losses, so the fallout from the scandal appeared limited. The bank disclosed those finding to federal authorities before releasing its second-quarter earnings and restating its numbers for the first quarter.

So has Dimon, who came sailed through the financial crisis without a scratch–unlike say Goldman’s Lloyd Blankfein–once again emerged as a champion? Maybe, but a lot will depend on what the investigations turn up and whether it fits with Dimon’s attempt to portray the now $5.8 billion trading debacle as an isolated risk management failure–potentially carried about by a small group of traders bent on concealing their actions.

As Emily Flitter and David Henry have been reporting over the past few weeks, Dimon’s narrative has begun to take some hits. The once small group of people believe to be involve now includes at least 7 current or former employees who have hired lawyers, including several risk officers. On Wednesday,  Reuters reported a fourth trader who worked under Bruno Iksil, the man nicknamed the London Whale because of the big bets he has taken on, is now also drawing scrutiny.