Whales, as we all know from school and trips to Sea World, frequently need to come up for air. Just like it's biological cousin, finance's London Whale also apparently needs to keep resurfacing.

JPMorgan Chase (JPM 3.55%) is reportedly suing Javier Martin-Artajo, supervisor of Bruno Iksil, the so-called London Whale whose outsize trading position in the derivatives market cost the bank at least $5.8 billion over the past year. No details of the claims against him have been made public, but this could be the superbank's way of directing the blame, staying one step ahead of regulators, and possibly blunting any action they might be considering.

Tired as investors might be of this story, this is good news for them.

The control freak
According to Financial Times, JPMorgan filed its claim against Martin-Artajo in London's High Court last week. Martin-Artajo, however, apparently hasn't been served with the claim himself. Under British law, JPMorgan has up to four months to do this, at which point he can respond to the charges.

We may then learn more about exactly what JPMorgan is up to here, but for the moment, it's clear that the Wall Street titan at least hasn't let up in its crusade to root out everyone and everything behind this expensive and embarrassing mess. This is very much in keeping with the style of Jamie Dimon, JPMorgan's infamously thorough and tough CEO.

Dimon is notoriously risk averse. JPMorgan Chase, which Dimon assumed control of in 2004, stayed largely out of the mortgage-backed securities and credit-derivatives mess in the run-up to the financial crash largely because of his aversion to excessive risk. He and his senior management had ample opportunity to get involved in the worst financial excesses of the 2000s, but they studiously avoided them, undoubtedly to the consternation of investors, at times, who saw competitors like Goldman Sachs (GS 1.86%) and Bank of America (BAC 2.19%) reaping the share-price rewards generated from record profits made off of America's credit bubble.

As such, the London Whale trading debacle (a $100 billion dollar bet gone wrong, almost the definition of excess in and of itself) was a tremendous shock to the careful Dimon and his like-behaving bank -- one he's been relentlessly on top of since news of the screw-up broke.

Blood in the water
Yes, this is the story that just won't go away, but it's better that Dimon and company are getting out ahead of things as much as possible. There are still numerous regulatory investigations in process, including the Office of the Comptroller of the Currency, the Securities and Exchange Commission, the Federal Reserve, and the U.K.'s Financial Services Authority. The Federal Bureau of Investigation is even looking into the matter, which means criminal action is a possibility.

If Martin-Artajo was unlawfully or unethically covering up Iksil's outrageous trading position, or the mounting losses, the bank would naturally want to get the jump on either U.S. or U.K. investigators. As Iksil's boss, Martin-Artajo is one of the people presumably aware of the bank's handling of the trade, so by going after him in this civil suit, the bank might be hoping to blunt whatever's coming down the line from regulators, or at least try and point them in a certain direction. By singling Martin-Artajo out, JPMorgan can say, "See, it was just this one guy causing all the trouble, and we got him already."

Of course, as we don't know full details of the filing yet. This is all speculation. But for the moment, it seems you can't keep a good whale down, especially a killer whale like Dimon. And for this, investors should be thankful.

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