If you're reasonably literate about the financial crisis, you probably know that the credit rating agencies have slipped through the carnage like a cat walking away from a knocked-over vase. With their opinions on publicly offered mortgage-backed securities protected by the First Amendment, Standard & Poor's and Moody's have won dismissals of the vast majority of MBS investor claims against them in state and federal court, despite powerful evidence from congressional investigations that they worked with underwriters to confer investment-grade ratings on securities backed by dreck. With one possible exception, the only surviving cases against rating agencies involve claims by investors in private placements, who have successfully argued that private ratings aren't protected free speech.

The near-spotless litigation record of the rating agencies means we've seen very little internal evidence, in the form of emails between rating execs, emails between the agencies and underwriters and deposition testimony from credit rating agency insiders. The only hard evidence on the agency's role in the economy's collapse came from a Senate report.

Until Monday.

In a series of filings in federal court in Manhattan, Abu Dhabi Commercial Bank and its lawyers at Robbins Geller Rudman & Dowd disclosed thousands of pages of internal communications and deposition transcripts to back their claims that S&P and Moody's are liable for fraud and negligent misrepresentation in connection with their rating of a structured investment vehicle underwritten by Morgan Stanley. Based on a declaration by plaintiffs that accompanied the documents, a huge percentage of the newly disclosed material has never previously been seen by the public -- and a good many of the documents deal not just with the Morgan Stanley SIV but more broadly with the rating process inside S&P and Moody's at a time when the two leading agencies were swamped with mortgage-backed securities to rate.

Robbins Geller also provided a helpful CliffsNotes version of the evidence in the form of an unredacted response to the defendants' motion for summary judgment. (A redacted version was filed in February, with page upon page blacked out.) This is a hot filing. Abu Dhabi quotes deposition testimony from "S&P's most senior quantitative analyst in Europe," for instance, that says "the ratings of (the SIVs) were inappropriate because the ratings of the underlying assets were not appropriate. So it leads to the conclusion that they should not have been rated." In other snippets quoted in the filing, rating agency analysts complained about "difficulties in explaining HOW we got to these numbers since there is no science behind it" and about "(making) up haircuts that were palatable to SIV issuers."

A lead S&P analyst on the deal, according to the plaintiffs, said in an email to his boss that the default rates the agency was using for asset-backed securities were guesswork. "From looking at the numbers it is obvious that we have just stuck our preverbal (sic) finger in the air," the analyst wrote.

Morgan Stanley, according to the plaintiffs' filing, bears at least as much blame as the rating agencies: The bank allegedly wrote the Moody's report on the SIV and read the S&P report before it was released to investors. The summary judgment opposition points to evidence that Morgan Stanley pressured the rating agencies to apply methodology that didn't suit the securities and to ignore the paucity of historical data in order to grant the SIV a rating it didn't deserve. By sending a supposedly "threatening" email to an S&P higher-up when an analyst proposed granting the SIV a BBB rating, Morgan Stanley boosted the rating to an A, the plaintiffs assert. In support, they quote an email from Morgan Stanley exec Greg Drennan, who had sent the allegedly menacing email: The bank's efforts, Drennan wrote, "did get us the rating we wanted in the end."

Morgan Stanley is represented in the case by Davis Polk & Wardwell, which referred me to a representative for the bank. She sent an email statement: "We believe the allegations in this case are without merit. We have defended ourselves vigorously throughout this litigation and will continue to do so." Moody's counsel James Coster of Satterlee Stephens Burke & Burke referred me to a Moody's representative who said in an email: "The plaintiffs' brief quotes selected emails out of context to support baseless allegations that are clearly refuted by the full record. Our rating opinions in this case were, as always, fully independent and based on robust and objective analytical criteria. We are confident that the claims against Moody's are without basis and that we will ultimately prevail on the merits."

S&P lead counsel Floyd Abrams of Cahill Gordon & Reindel referred me to a spokesman, who sent a statement: "The selective excerpts from emails cited in the plaintiffs' opposition to our summary judgment motion were chosen from thousands of pages of documents and are being used out of context to support a baseless case. We will continue to vigorously defend ourselves against it."

(Reporting by Alison Frankel)

Follow us on Twitter @AlisonFrankel, @ReutersLegal  | Like us on Facebook