Merrill Lynch is in discussions to sell its $6 billion (£3.02 billion) stake in Bloomberg, the financial news and data service founded and majority-owned by New York Mayor Michael Bloomberg.

Merrill chief executive John Thain has said he would like to sell the holding, and possibly half the group's 49.8% stake in fund management group Black-Rock. He is reported to have said the Bloomberg stake is worth $6 billion, but its is believed the first offer for it was closer to $3 billion.

The scale of Merrill's sell-offs in the wake of the subprime crisis and credit crunch will depend on how much more it has to take in writedowns on toxic loans and investments. Analysts predict another hit of as much as $4.2 billion when it reports second-quarter results later this month.

Discussions over a Bloomberg sale are at an early stage. Bloomberg, which is still 70%-owned by Michael Bloomberg, has first option on the shares, and Merrill is likely to look at offering some help in financing any transaction.

The privately held Bloomberg is reckoned by analysts to be worth up to $20 billion, and is estimated to have annual operating profits of about $1.5 billion.

Bloomberg's two major rivals, Reuters and Thomson, joined forces earlier this year in an £8.7 billion deal.