Dallas billionaire T. Boone Pickens may help finance a takeover of Exco Resources Inc., a natural gas producer with assets in Louisiana’s Haynesville shale formation, by its chairman, Douglas Miller.

Pickens is an “approved financing source” for Miller, who is also Exco’s chief executive officer, and will be allowed to see confidential financial information about the company, according to a Jan. 26 letter to Pickens from a board committee that is negotiating a potential transaction. Pickens also signed a 15-month confidentiality agreement, according to a regulatory filing today.

In a separate filing today, New York-based financier Wilbur Ross said he’s increased his stake in Exco to 9.7% from 7.5%. Ross said in December he wants to discuss “strategic alternatives” for Exco’s future with the board, including a potential merger or the sale of its assets.

“We think that the stock is attractive and that is why we bought more,” Ross said in an e-mailed statement today.

Exco’s board is considering Miller’s Oct. 29 offer of $20.50 a share, or $4.36 billion, to take the company private. The price represents a 38% premium to Exco’s closing price that day. He said at the time he had backing from three of the largest shareholders: Pickens, Oaktree Capital Management LP and Ares Management LLC.

‘Strategic Alternatives’

Exco was unchanged at $19.85 a share in New York Stock Exchange composite trading.

The company’s board of directors formed a committee Jan. 13 to consider “strategic alternatives” to Miller’s bid. The board also adopted a shareholder rights plan that imposed new requirements on entities acquiring 10 percent or more of the company’s stock.

Dallas-based Exco’s proved gas reserves rose 56% to the equivalent of 1.5 trillion cubic feet in 2010 from 959 billion cubic feet in 2009, mostly because of an increase in Haynesville shale production, the company said in a Jan. 13 statement.

Miller didn’t immediately return a call seeking comment. Jay Rosser, a spokesman for Pickens, declined to comment in an e-mail.

Ross said in a Dec. 11 e-mail that Exco’s holdings in the Haynesville and Marcellus shale formations might become more valuable in a few years if the price of natural gas rises.

“We believe it will be a major beneficiary if our forecast trends do emerge,” Ross wrote. “We look forward to lively discussions with management and the Special Committee regarding the future of the company.”