Microsoft may have some competition if it is seeking to buy DoubleClick after reports that Google is considering making a bid for the web advertising firm.  

Reports in yesterday's Wall Street Journal said that DoubleClick, owned by private-equity group Hellman & Friedman, has received interest from Google, Yahoo and Time Warner's AOL, as well as a reported $2bn bid from Microsoft.

However, a deal by Google would be likely to attract the interest of regulators, given the search giant's dominant position in the online advertising space.

Hellman & Friedman bought DoubleClick for $1.1bn in 2005. It has been suggested that the current round of leaks to the Wall Street Journal is nothing more than a PR campaign to encourage a bidding war between interested parties.

None of the companies alleged to be interested in DoubleClick has made an official comment on any bid.

DoubleClick has hired investment bank Morgan Stanley to examine options for raising capital, including a possible stock market listing.