ELECTRICITE de France has about three months to oppose the takeover of Constellation Energy Group by Warren Buffett's Mid-American Energy Holdings, CM-CIC Securities said yesterday.

EDF hasn't "lost out" on Constellation because it "remains the best partner for any utility wanting to launch an EPR" nuclear reactor, CM-CIC Securities analyst Patrice Lambert-de Diesbach said.

The French utility has a joint venture with Constellation, in which it has a 9.5 percent stake, to develop so-called new generation reactor models called EPRs, or Evolutionary Power Reactors, that are capable of producing about 1,600 megawatts of electricity, Bloomberg News said.

EDF said it offered to acquire Constellation with buyout firms KKR & Co and TPG Capital for US$6.2 billion, 32 percent more than Buffett agreed to pay.

The agreement for Buffett's MidAmerican to buy Baltimore-based Constellation for US$4.7 billion, or US$26.50 a share, wasn't adequate, Paris-based EDF said.

Constellation Chief Executive Officer Mayo Shattuck said the Buffett deal was "superior" after the largest United States power marketer plunged 58 percent in the preceding three days.

"EDF remains in a privileged position to defend minority rights of shareholders," wrote CM-CIC's Lambert-de Diesbach. "Whatever comes out of a debate between experts on the complexity of its offer, EDF's bid is 32 percent higher."

The filing was made as Shattuck and MidAmerican CEO Greg Abel said they expected to close their transaction in a year or less.