UBS AG's Chief Executive Oswald Grubel wants to run the Swiss bank's U.S. brokerage unit for at least three years and sell it later at some point, CNBC said on Friday.

The world's second largest wealth management firm was approached by former Merrill Lynch's wealth management head Robert McCann and private equity firm Kohlberg Kravis Roberts & Co to acquire its unit in the United States, the U.S. television network said.

A UBS spokeswoman in New York said the bank has repeatedly mentioned in the past that its U.S. business was not for sale, and declined to give further comments.

CNBC said McCann and Wachovia Securities Chief Executive Daniel Ludeman were both in the running to lead UBS U.S. unit.

Media reports have said that UBS has considered selling its U.S. wealth management business, which consists mainly of the Paine Webber unit acquired in 2000 for roughly $10 billion, for a long time.

The Swiss bank has lost billions of dollars in the global financial crisis. On Friday, it struck a deal with U.S. tax authorities over the identities of 52,000 Americans suspected of using secret bank accounts to hide nearly $15 billion in assets.

UBS is expected to post a second-quarter loss of 1.1 billion Swiss francs ($1.01 billion) on Tuesday and analysts expect the bank to continue to suffer billions of francs of client withdrawals at its wealth and asset management divisions. 

 (Reporting by Christian Plumb and Juan Lagorio; Editing by Leslie Gevirtz)