Bethany McLean is a contributing editor at Vanity Fair and bestselling author. Her recent book is "Shaky Ground: The Strange Saga of the U.S. Mortgage Giants," published by Columbia Global Reports.

“This gags me.” So said Elizabeth Warren in response to a Quora user, who asked, “What do you think are the real reasons that no Wall Street executives have been prosecuted for fraud as a result of the 2008 financial crisis?” Her answer, which she expounds on more thoroughly in her report Rigged Justice, is, “Weak enforcement begins at the top.”

I’ve always thought the lack of prosecution was way more complicated than a simple lack of will, in part because there is a difference between criminally prosecutable behavior and that which is morally reprehensible. But I’m not sure whether we’ll ever know the real answer. Newly public documents from the Financial Crisis Inquiry Commission show that the FCIC referred a handful of matters to the Justice Department for possible prosecution. Most of the time, nothing happened. In the cases where something did happen, our modern system of justice—the special one that applies to big business, that is—means that those of us on the outside—citizens, on whose behalf justice is supposed to be served—will never know the underlying truth.

Don't we at least deserve to understand?

A little background: The FCIC was set up to investigate the causes of the financial crisis. The commission didn’t have either the authority or the resources to do a criminal investigation. But as the documents show, a number of matters—involving Goldman Sachs, AIG, Merrill Lynch, Citigroup and Fannie Mae—were referred to the Attorney General. No criminal prosecutions arose from any of those. (In Citigroup’s case, the SEC settled with the company and two executives in the fall of 2010 for a paltry sum. The Commission drily noted, “The SEC’s civil settlement ignores the executives running the company and Board members responsible for overseeing it. Indeed, by naming only the CFO and the head of investor relations, the SEC appears to pin blame on those who speak a company’s line, rather than those responsible for writing it.”)

Why? Well, really, we have no idea.

The FCIC also referred what I’ve always thought was the area in which Wall street had the most exposure to the criminal authorities. That’s what Wall Street firms told investors they were buying when they bought mortgage backed securities. Or as the FCIC labeled it, “Potential Fraud: False and Misleading Representations about Loan Underwriting Standards by UBS and Other Issuers.” (UBS is mentioned specifically only because the FCIC first discovered what was happening by looking at UBS.)

Back in 2010, FCIC investigators found that a firm called Clayton Holdings, which was hired by Wall Street firms to investigate the mortgages that were being packaged into securities, was finding that they were not what they were supposed to be. Clayton examined almost a million mortgages, according to the FCIC’s analysis, and found that almost 30% failed to meet the underwriting standards that had been set, like the amount of money the borrower had put down, and didn't have other factors that might compensate for that. And yet, Wall Street waived almost 40% of those questionable loans, sticking them into securities anyway. (Clayton kept track of the waivers in order to protect themselves from potential liability.) The banks didn’t tell investors. "In some cases we felt that we were potted plants," Keith Johnson, president of Clayton Holdings, told Reuters at one point.

It seems that in the run up to the crisis, the big banks were doing their best to play ostrich. In its public report, the FCIC wrote, “Only a small portion—as little as 2% to 3%—of the loans in any deal were sampled. When those loans turned up turnips, the banks didn't do the logical thing, and have Clayton go investigate a bigger sample. Instead, they hid their heads in the sand—and didn't bother to inform their investors of any of this. “Prospectuses for the ultimate investors in the mortgage-backed securities did not contain this information, or information on how few loans were reviewed, raising the question of whether the disclosures were materially misleading, in violation of the securities laws,” the FCIC wrote in its report.

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