Williams Cos. Inc. (WMB) said Sept. 28 it agreed to be acquired by Energy Transfer Equity LP (ETE) in a stock-and-cash deal valued at about $37.7 billion, including debt, three months after it rebuffed Energy Transfer's $53.1 billion offer.

Energy Transfer's offer of $43.50 per share represents a premium of 4.6% to Williams' close on Sept. 25.

Williams, which had rejected the earlier offer in June saying that it significantly undervalued the company, has lost nearly a third of its market value since then.

Williams shares fell 2% to $40.61 in premarket trading on Sept. 28.

Williams stockholders electing to receive stock will get 1.8716 Energy Transfer shares for each share held, the companies said in a joint statement.

Energy Transfer had previously said that its offer was contingent on the termination of Williams' pending acquisition of natural gas MLP Williams Partners (WPZ).

Williams Partners said on Sept. 28 it would terminate the deal and would receive $428 million in termination fee from Williams.

Williams operates natural gas pipelines spanning the Gulf of Mexico to the Canadian oil sands, while Energy Transfer operates natural gas, crude and refined product pipelines.