The hedge fund run by the activist investor Edward S. Lampert increased its stake in Citigroup Inc. by 63% in the second quarter, to 24.8 million shares, according to a regulatory filing late Tuesday.
Mr. Lampert's RBS Partners LP, a unit of ESL Investments Inc. of Greenwich, Conn., owned about 0.4% of the Citi's outstanding shares at the end of the second quarter. Shares of the $2.2 trillion-asset New York company made up about 8% of RBS Partners' $16.5 billion investment portfolio on June 30, the filing said.
A spokesman for Mr. Lampert did not return calls for comment. Citi would not discuss the investment.
RBS Partners first reported owning shares of Citi in the first quarter, as several Citi critics were raising the idea of splitting up the company.
Mr. Lampert is known for his engineering of the deal to combine Sears Roebuck & Co. and Kmart Holding Corp. He is now the chairman of Sears Holdings Corp.
