NEW YORK — Centerbridge Partners L.P., a private investment firm with approximately $20 billion in capital under management, has agreed to acquire Scottsdale, Ariz.-based P.F. Chang’s China Bistro, Inc. for $1.1 billion. The move would make P.F. Chang’s a private company.

Under terms of the agreement, Centerbridge will acquire all of the outstanding shares of P.F. Chang’s common stock for $51.50 per share in cash. This represents a premium of approximately 30% over the average closing price of the company’s common stock for the 30-day period ended April 30. Shares of P.F. Chang’s climbed 30% to $51.64 in early trading on May 1, the day the deal was announced.

A tender offer for all of the outstanding shares is expected by no later than May 15, the companies said. For the transaction to close, about 83% of the shares need to be tendered. P.F. Chang’s said it also may seek out competing bids until May 31.

In financial results issued May 1, P.F. Chang’s posted net income of $6,276,000, equal to 30c per share on the common stock, in the first quarter ended April 1. This compared with income of $10,596,000, or 47c per share, in the same period a year ago. Revenues were $318,908,000, up narrowly from $317,369,000.

“We have great respect for P.F. Chang’s, its brands, and the company’s strong commitment to its customers, employees and partners,” said Jason Mozingo, senior managing director of Centerbridge. “We look forward to working with management to lead the company through its next phase of growth and development.”

Rick Federico, chairman and chief executive officer of P.F. Chang’s, said the move to a private company “will provide us with greater flexibility to focus on our long-term strategic plan of elevating our guest experience, enhancing our value proposition, growing traffic and improving the performance of our brands.”

P.F. Chang’s owns and operates two restaurant concepts in the Asian niche. P.F. Chang’s China Bistro (204 units) features a blend of Chinese-inspired cuisine in a contemporary bistro setting. Pei Wei Asian Diner (171 units) offers a menu of freshly prepared, wok-seared, pan-Asian cuisine. The first P.F. Chang restaurant opened in 1993 in Scottsdale, while the first Pei Wei restaurant opened in the Phoenix metro area in 2000.

Since 2009, P.F. Chang’s China Bistro and Unilever have engaged in a licensing agreement on a line of frozen Asian entrees marketed in the United States under the P.F. Chang’s brand. Last month, the P.F. Chang’s Home Menu products topped the list of 2011 New Product Pacesetters from Chicago-based market research firm SymphonyIRI Group. The products brought in $101.6 million during their first year on the market. P.F. Chang’s line of frozen entrees, which tout signature bold flavors, had 84% distribution with 7.1% trial rate and 31% repeat rate, according to SymphonyIRI.