Dynegy Inc. said the New York Public Service Commission approved a $665 million takeover bid by investor Carl Icahn. Commission approval is one of the conditions for the takeover bid from Icahn Enterprises LP to go forward.

On Dec. 22, Icahn offered to buy all the shares of Dynegy common stock for $5.50 each. Dynegy’s statement said the Justice Department and Federal Trade Commission have agreed to waive the waiting period outlined under anti-trust laws. The only remaining regulatory approval the companies need is from the Federal Energy Regulatory Commission, Dynegy said.

In late November, Dynegy said that a lack of shareholder support for a proposal by Blackstone Group to take over the company led both companies to terminate Blackstone’s proposed acquisition.

In December, Dynegy’s board unanimously voted to recommend that shareholders accept the offer, saying the deal is in the best interest of all Dynegy shareholders. Icahn, Dynegy’s largest shareholder, already owns a 9.9 percent stake in the Houston-based company.

Read more news and features on the business of power generation.