Twenty-five Nuveen Investments Inc. funds sued American International Group Inc., claiming that the company and executives committed securities fraud leading to the U.S. financial crisis that intensified in 2008, Bloomberg News reported yesterday. Also named yesterday as defendants in a 237-page complaint in federal court in Chicago were former Chief Executive Officer Martin J. Sullivan, ex-Chief Financial Officer Steven Bensinger and Joseph Cassano, who led the AIG Financial Products unit. The funds accused the company, Sullivan and others of violating Illinois and federal securities laws, common law fraud and unjust enrichment. They asked for unspecified money damages.