Citigroup Inc., which wants to make Nikko Cordial Corp. a 100 percent subsidiary, agreed Wednesday to revise its share-swap contract with the Japanese brokerage after its stock price plunged amid the ongoing U.S. subprime mess.

Under the original Oct. 31 agreement, the U.S. financial giant was to offer its shares for ¥1,700 per Nikko Cordial share to the brokerage's stockholders, based on Citigroup's average stock price between Jan. 15 and 17, 2008.

The initial agreement had a clause stating that Citigroup's average stock price must be between $37 and $58. But the revised agreement unveiled Wednesday deletes the clause because the megabank's shares have continued to plunge in the midst of the subprime mortgage loan crisis.

Management apparently revamped the deal fearing the initial agreement would not persuade Nikko Cordial's shareholders to sell their stock. Citigroup closed at $35.90 Tuesday in New York.