Nikko Cordial Corp., the Japanese securities unit of Citigroup Inc., said Monday second-quarter profit more than doubled on trading gains and the sale of a stake in Seibu Holdings Inc. railway, hotel and resort chain.

Net income rose to ¥24.1 billion for the three months ended Sept. 30, compared with ¥10.2 billion a year earlier, as Nikko earned more from investments and asset management, the Tokyo-based brokerage said. Revenue rose to ¥138.3 billion from ¥118 billion.

Nikko posted the biggest quarterly profit among Japanese brokers, beating larger Nomura Holdings Inc. and Daiwa Securities Group Inc, which were hit by a decline in equity underwriting and by losses linked to defaults on U.S. mortgages. Nikko, integrated under Citigroup's Japan umbrella in August, is developing products with the bank for distribution through its nationwide branch network.