This week, five Wall Street banks pleaded guilty to felony charges related to interest-rate rigging and foreign-exchange manipulation.

The guilty pleas mean the banks are literally felons, and it's a distinct shift in the way law enforcement has dealt with Wall Street in the past.

Lawsuits and legal fees are nothing new for the banks: Since the financial crisis, they have essentially become the cost of doing business on Wall Street.

Now, apparently, that cost includes both legal fees and criminal charges. The thing is, no one seems to be fazed.

This case has nothing to do with the financial crisis. Rather, a couple years ago, traders from a handful of banks manipulated the London Interbank Offered Rate, an important interest rate used around the world as a benchmark for mortgages and other loans. Other traders manipulated the prices at which banks bought or sold currencies.

No individual traders from the guilty banks, which include Barclays, Citicorp, JPMorgan, RBS, and UBS, have been held criminally accountable. But the banks are paying $5.6 billion in fines (together with Bank of America, which is only paying a civil penalty, not a criminal one).

You might think the criminal charges are a big win for regulators. Finally, the banks are taking responsibility for their crooked employees, rather than pawning the blame off on overseas subsidiaries!

But the reality is probably less of a triumph for regulators than it seems.

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Peter Henning, a Wayne State University securities law professor, thinks the whole ordeal will be just another write-off for the banks, like any "one-time" legal fee you might find in a bank's earnings report.

He wonders if, for the banks, pleading guilty to felonies and paying criminal fines is just "another cost of doing business" — a routine but acceptable drag on profits; no different than paying salaries, rents, and utility bills.

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The banks are paying a hefty amount of money for the crimes (Barclays alone is paying $2.4 billion). But it's not like they haven't had to do that before.

The difference this time is that some people were expecting that criminal charges – rather than civil charges – would lead to some sort of collateral consequence for the banks.

Instead, all five banks were granted waivers from the SEC that will allow them to carry on with business as usual. They won't have to deal with any limitations on loans, deposit-taking, securities issuing, or other restrictions that they would otherwise have faced.

The waivers thing is not new, either. SEC Commissioner Kara Stein, who is not a fan of the procedure, pointed out that Barclays has already gotten three waivers since 2007. UBS has had seven; JPMorgan has had six, and RBS has had three.

In return for this round of waivers, though, the banks agreed to a three-year probation period in which they promise not to commit any more felonies.

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