The banks of America should probably start replacing “Most Wanted” posters of bank robbers with head shots of John Quinn and his partners at Quinn Emanuel Urquhart Oliver & Hedges. As we’ve told you about a million times, Quinn litigators — who aren’t encumbered by corporate client relationships — have been having a grand old time filing cases against banks since the economy went into free-fall. Here’s our most recent coverage, for example, of Quinn’s fraud case against J.P. Morgan, brought on behalf of the parent company of Washington Mutual; and here’s news of its recent suit on behalf of Access Industries against Morgan.

Quinn’s latest targets are Citibank and Credit Suisse. In a 65-page New York state Supreme Court complaint filed on Monday, Quinn’s client, the bond insurer Ambac Credit Products, alleges that because of fraud by the banks, it was induced to provide $2 billion in coverage for collateralized debt obligations that were secured by high-risk subprime mortgages. [Hat tip: Courthouse News] Just before Ambac provided coverage, the complaint asserts, Citi claimed the mark-to-market valuation of the CDOs was 96 cents on the dollar, when, Ambac alleges, it was actually no more than 79 cents.