On July 18, 2012, the SEC issued a Press Release that stated: "The Securities and Exchange Commission today charged the U.S. investment banking subsidiary of Japan-based Mizuho Financial Group and three former employees with misleading investors in a collateralized debt obligation (CDO) by using 'dummy assets' to inflate the deal's credit ratings. The SEC also charged the firm that served as the deal's collateral manager and the person who was its portfolio manager."

In the Complaint the SEC stated: "This action arises from the structuring, marketing and rating of a hybrid collateralized debt obligation ('CDO') called Delphinus CDO 2007-1 ('Delphinus'). Delphinus was a mezzanine CDO backed by subprime bonds, which means that the collateral held by Delphinus was largely composed of subprime Residential Mortgage Backed Securities ('RMBS') that were rated slightly higher than junk bonds, and credit default swaps referencing subprime RMBS. Mizuho Securities USA, Inc. ('Mizuho') structured, marketed and obtained ratings for this $1.6 billion CDO in mid-2007, when the housing market and the securities referencing it were showing signs of distress. The marketing materials for Delphinus -- including the Offering Memorandum -- represented that the notes issued by the CDO would obtain certain specific ratings from three credit rating agencies, including Standard & Poor's ('S&P'). Receipt of those ratings was a condition precedent to Delphinus's closing and the sale of the CDO notes. Undisclosed to purchasers of Delphinus notes, however, certain Mizuho's employees provided S&P inaccurate and misleading information. Investors were mislead because notes were issues with ratings obtained by the conduct of Mizuho employees."

On July 19, 2012, the SEC issued a Litigation Release that stated: "The Securities and Exchange Commission has charged the U.S. investment banking subsidiary of Japan-based Mizuho Financial Group and three former employees with misleading investors in a collateralized debt obligation (CDO) by using 'dummy assets' to inflate the deal's credit ratings. The SEC also charged the firm that served as the deal's collateral manager and the person who was its portfolio manager."

On July 24, 2012, Federal District Judge Miriam Goldman Cedarbaum entered Final Judgment against Mizuho Securities USA Inc., pursuant to the SEC and Mizuho Securities USA Inc.'s consent.

On September 21, 2015, Federal District Judge Loretta A. Preska ordered the establishment of a Fair Fund and approved the Distribution Plan. Judge Preska also ordered the appointment of Nancy Chase Burton, an employee of the SEC, as the Plan Administrator.