DETROIT—Automaker General Motors Corp. has some directors and officers liability insurance to cover its portion of a proposed $303 million securities fraud class action settlement.

In its Aug. 7 10-Q filing for the second quarter, Detroit-based GM disclosed that it reached a $277 million settlement in July with plaintiffs that accused the company of improper accounting, overstating income and other misdeeds between April 13, 2000, and March 30, 2006.

GM has $100 million in insurance to respond to the settlement, a spokeswoman said. The company's 10-Q explanation of the settlement refers to $200 million of coverage, but the spokeswoman said half of that coverage is for settlements of litigation the company is not disclosing.

The spokeswoman would not identify GM's insurers.

As part of the settlement, New York-accounting and consulting firm Deloitte & Touche L.L.P. will contribute $26 million.

A Deloitte spokeswoman would not say whether any insurance would cover the firm's settlement.

The total settlement of $303 million, if approved by a federal court judge in Detroit, would rank as the 25th-largest securities fraud settlement ever, according to figures provided by financial risk management consultant RiskMetrics Group Inc. of New York.

The lead plaintiffs in the case were institutional investors Deka Investment GmbH, and Deka International S.A., subsidiaries of German financial institution DekaBank.

Labaton Sucharow L.L.P. of New York and Grant & Eisenhofer P.A. of Wilmington, Del., represented the plaintiffs.

Plaintiffs attorney Eric Belfi, a partner at Labaton, noted that the settlement was reached in a relatively quick two-and-a-half years. Most settlements take between three and five years to hammer out, he said.

GM also disclosed in its 10-Q that it settled a derivative action lawsuit related to the securities fraud claim. The company has agreed to implement some corporate governance changes over the next four years and pay up to $7 million of plaintiffs' attorneys fees.