ELECTRICITE de France SA, the world's biggest operator of nuclear reactors, backed out of a takeover battle for Constellation Energy Group Inc, as the credit crisis thwarted deal-making.

Constellation shares fell 6 percent in New York on Wednesday after the prospect of a bidding war evaporated between EDF and Warren Buffett's MidAmerican Energy Holdings Co, which offered US$4.7 billion for the Baltimore-based power company last month.

Rio Tinto Group yesterday also cited market turmoil for possibly delaying US$10 billion of asset sales.

The global lending freeze is blocking acquisitions.

Rio is reviewing its spending and project costs. Xstrata Plc this month abandoned a US$8.7-billion hostile bid for platinum producer Lonmin Plc and Sterlite Industries (India) shelved its US$2.6-billion purchase of Asarco LLC.

"It's a very, very difficult market to float any kind of debt securities, here or in Europe," Gregory Phelps, who manages US$2.5 billion at MFC Global Investment Management in Boston, including preferred shares of Constellation, said in an interview with Bloomberg News.

EDF, which has a 9.5 percent stake in Constellation, said it will work with United States partners to develop at least four new-generation reactors, according to a statement.

The French utility said it was pulling out of the race to buy Constellation because of the "current state of financial markets and in particular the difficult credit market."

US stocks yesterday plunged the most since the crash of 1987.

The value of takeovers announced this year fell 30 percent to US$2.3 trillion as of September 30, according to data compiled by Bloomberg News.