(Reuters) - DBRS Ltd, the privately held credit rating agency that competes with Standard & Poor's Financial Services LLC, Moody's Corp (>> Moody's Corporation) and Fitch Ratings Inc, is exploring a sale, according to people familiar with the matter.

DBRS owner Walter Schroeder, who founded the firm in 1976 and is now in his 70s, has hired investment bank Perella Weinberg Partners LP to run an auction for the firm, the people said on Tuesday. Private equity firms are among the parties interested, the people added.

The people said DBRS could fetch several hundred millions of dollars in a sale. The sale process is part of a wider exploration of strategic alternatives driven by Schroeder's estate planning, one of the people added.

The sources cautioned that a deal is not certain and asked not to be identified because the sale process is confidential. A DBRS spokesman declined to comment, while a Perella Weinberg spokeswoman did not respond to a request for comment.

Toronto-based DBRS is the world's fourth-largest credit rating agency. It rates the debt of companies, local authorities and countries, as well as structured finance products such as commercial mortgage-backed securities.

DBRS got a modest start 30 years ago in Toronto, when Schroeder left a Bay Street investment dealer to start rating short-term commercial paper. Two years later, the firm began covering corporate and sovereign debt.

While Standard & Poor's, Moody's and Fitch still account collectively for more than 95 percent of the ratings market, DBRS, with a 2 percent market share, has focussed on structured finance products, countries and financial institutions, although it rates all asset classes.

Daniel Curry, a former Moody's managing director, currently serves as chief executive officer of DBRS.

In a Reuters interview in 2007, Schroeder said he had regularly received overtures to acquire the company but was not interested at that stage.

"For the time being, we're fine with the way we are. It would probably take quite an overwhelming offer of some sort to get me to change my mind," Schroeder said at the time.

Private equity firms have shown strong interest in acquiring financial services companies in recent years. A consortium led by Carlyle Group LP (>> The Carlyle Group LP) acquired financial advisory and investment banking firm Duff & Phelps Corp last year, while CVC Capital Partners bought restructuring advisory firm AlixPartners LLP in 2012.

(Reporting by Greg Roumeliotis in New York; Editing by Gunna Dickson)

By Greg Roumeliotis

Stocks treated in this article : Moody's Corporation, The Carlyle Group LP