Exelon Corp pulled its hostile $7.7 billion bid for NRG Energy Inc on Tuesday after NRG shareholders rejected an Exelon-backed slate of directors.

Exelon, the largest U.S. nuclear power company, said it was unwilling to raise its offer to a level that would undermine the value created by the proposed deal.

The NRG shareholders have spoken, and Exelon will move on. We wish NRG and its owners well, Exelon Chief Executive John Rowe said in a statement.

Shareholders of NRG, an independent power producer, rejected all of Exelon's director nominees, as well as its proposal to expand NRG's board. At the annual meeting on Tuesday, shareholders re-elected the four directors nominated by NRG, with about 75 percent of the shares voted backing those nominees.

Exelon warned last week that it would pull its offer for NRG if none of its nominees were elected. Exelon made its initial hostile bid in October and raised it earlier this month.

It was offering 0.545 Exelon shares -- worth around $28.94 Tuesday morning -- for each NRG share. NRG rejected the bid as too low.

A source close to the matter said it would be absolutely shocking to see Exelon revisit the bid after being rebuffed by NRG shareholders.

STANDING ALONE

Both companies touted their value as stand-alone entities and appear likely to remain independent, at least in the near term.

NRG looked for other buyers after Exelon began its pursuit, but no other offers emerged.

NRG Chief Executive David Crane said on Tuesday the company had received expressions of interest from other potential buyers, including major European utilities, U.S. utilities and cash buyers such as private equity.

But potential European buyers, who expressed interest in NRG before the recent climate change bill was floated in the U.S. Congress, want certainty on climate change, he said.

They're interested, but they're waiting, Crane told reporters after the annual meeting.

Exelon said in a statement that it would focus on its plan to expand its nuclear output, as well as taking advantage of its position as a low-carbon power provider, to improve its profits.

Bill Von Hoene, executive vice president and general counsel for Exelon, said the company was not currently considering any other acquisitions.

We have nothing on the table to do anything like this, he told reporters.

Shares of NRG were up 66 cents, or 2.8 percent, to $24.21 in midday trade on the New York Stock Exchange, while Exelon was up $1.11, or 2.1 percent, at $53.16.

(Reporting by Matt Daily and Michael Erman; Editing by Derek Caney and John Wallace)