Berkshire Hathaway chairman Warren Buffett is backing a consortium vying for Yahoo Inc's internet assets that includes Quicken Loans Inc founder Dan Gilbert, people familiar with the matter said on Friday.

While there is no certainty that the consortium will prevail in the auction, the interest of Buffett and Gilbert is a boost for the Sunnyvale, California-based company, which has been surpassed in recent years by rivals such as Alphabet Inc in the race for internet users and advertising dollars.

The consortium's participation in the sale process also represents a challenge to US telecommunications carrier Verizon Communications Inc, whose deal to acquire AOL last year for $4.4 billion has made it a favourite to prevail in its bid for Yahoo's assets among industry analysts.

The consortium is in the second round of bidding in the auction for Yahoo's assets, the people said. Buffett is helping finance the offer, one of the people added.

It is not clear whether Gilbert, a billionaire who also owns the US basketball team Cleveland Cavaliers, is using Quicken Loans in any way as part of the consortium's bid.

The sources asked not to be identified because the details of the sale process are confidential. Buffett offered no immediate comment when reached by telephone. A Quicken Loans spokeswoman declined to comment on behalf of Gilbert, while Yahoo did not immediately respond to a request for comment.

Reuters reported last month that Yahoo had shortlisted close to 10 bidders in the auction for its assets, with most offers coming from private equity firms. – Reuters