Carlyle and Warburg Pincus are close to buying Canada's DBRS

A consortium of US-based private equity majors Carlyle Group and Warburg Pincus is reportedly in advanced talks to acquire Canada-based credit rating agency DBRS for over $500m (£318.13m).

Carlyle and Warburg appeared to be in the lead to acquire DBRS after final bids were submitted this week, Reuters reported.

The auction for DBRS has also attracted Canadian private equity firm Birch Hill Equity Partners, the report added.

No exclusivity has been awarded to any bidder. Carlyle and Warburg Pincus were in the lead partly because of their international footprint, which can help DBRS expand further globally.

In addition, it is unclear whether or not DBRS owner Walter Schroeder, who founded the firm in 1976 and is now in his 70s, will retain a stake in the firm.

Carlyle, Warburg, DBRS and Birch Hill would not comment on the takeover rumours to Reuters.

Toronto-based DBRS is the world's fourth-largest credit rating agency after Standard & Poor's Financial Services, Moody's and Fitch Ratings.

Daniel Curry, a former Moody's managing director, is the firm's chief executive.

DBRS rates the debt of companies, local authorities and countries, alongside structured finance products such as commercial mortgage-backed securities (CMBS).

Schroeder hired investment bank Perella Weinberg Partners to run the auction, Reuters reported in August.

Private equity firms have targeted financial services firms in recent years.

In 2013, a consortium led by Carlyle bought financial advisory and investment banking firm Duff & Phelps. In 2012, London-based CVC Capital Partners picked up a majority stake in restructuring advisory firm AlixPartners.