Oswald Gruebel, chief executive of UBS, wants the Swiss bank to retain its US retail brokerage business UBS Financial for at least three years, according to a report by CNBC, the US television network.

The Zurich-based bank turned down an offer from Robert McCann, Merrill Lynch's private-client unit chief until he stepped down shortly after Merrill became part of Bank of America, and buyout specialists Kohlberg Kravis Roberts with an offer to acquire its US brokerage, according to the report.

Rumours about an impending sale of UBS's retail brokerage business have been circulating in the press for some time.

But a UBS spokesman says the bank's US retail business isn't in fact on the block.

Though CNBC didn't specify why UBS turned down the offer from McCann and KKR, it said that Mr Gruebel wants to keep its US wirehouse for another few years - seemingly an indication that the former Credit Suisse executive doesn't want to preside over a high-profile sale into a depressed mergers and acquisitions market.

UBS entered the US private-client business when it paid about $10 billion for Paine Webber in 2000. In those heady days, soon after the Gramm-Leach-Bliley Act enabled the unification of US banks, brokerages and insurance companies for the first time in nearly 70 years, it seemed there were limitless possibilities for cross-selling in the private client and investment banking arenas.

Since then, however, UBS has reportedly had a tough time absorbing its US brokerage, which, with fewer brokers on staff now than in 2000, is the smallest of the five wirehouses.