A federal judge yesterday signaled that he will not rubber-stamp Citigroup Inc.'s proposed $590 million settlement of a shareholder lawsuit accusing it of hiding tens of billions of dollars of toxic mortgage assets, Reuters reported yesterday. U.S. District Judge Sidney Stein asked lawyers for the bank and its shareholders to address several issues at an April 8 fairness hearing, including requested legal fees and expenses of roughly $100 million, and the absence of payments by former Citigroup executives. Citigroup awaits a decision from the federal appeals court in New York on whether Stein's colleague Jed Rakoff properly rejected a $285 million settlement with the U.S. Securities and Exchange Commission over the alleged defrauding of investors. The $590 million settlement resolved claims by Citigroup shareholders from February 26, 2007 to April 18, 2008 that the bank failed in those years to properly write down risky debt, often backed by subprime mortgages, and concealed the risks.