Charles O. “Chuck” Prince and Robert Rubin were among Citigroup Inc. officials who knew 2007 losses were mounting on mortgage assets that U.S. regulators have faulted the bank for not disclosing, a court filing shows. Prince, the bank’s chief executive officer at the time, and Rubin, then-chairman, knew the highest-rated segments of subprime mortgage-backed securities were the source of about $200 million in new losses in October 2007, the Securities and Exchange Commission said yesterday in a filing at federal court in Washington. In July, the agency accused the bank and two other executives of failing to disclose $40 billion in subprime assets before losses surged. It didn’t target Prince and Rubin. U.S. District Judge Ellen Huvelle asked the agency last month to explain what senior executives knew as she considers approving Citigroup’s $75 million settlement with the regulator. The agency’s identification of Prince and Rubin may trigger questions from the judge about why the agency didn’t bring claims against more people, said Peter Henning, a professor at Wayne State University Law School in Detroit.