SAN FRANCISCO - FORMER star technology investment banker Frank Quattrone is advising Google as the Web search leader mulls its strategy amid Microsoft Corp's move to buy Yahoo Inc , a source familiar with the arrangement said on Thursday.

Mr Quattrone underwrote some of the biggest initial public offerings during the late-1990s technology boom while at Credit Suisse First Boston.

Last month, Mr Quattrone announced that he and some former colleagues had started Qatalyst Group, a tech-focused investment banking boutique based in San Francisco, to provide merger and corporate finance advice to technology companies.

'He is advising the company,' the source said on Thursday of Google's decision to hire him, offering no further details.

A Google spokesman declined to comment.

Yahoo announced on Wednesday it had agreed to a test of whether it should turn over its Web search advertising sales to Google so it can focus on other efforts. Sources say the test is part of a planned three-way alliance to combine Yahoo with Time Warner Inc's AOL to ward off Microsoft Corp's two-month-old, US$42 billion (S$57.5 billion) takeover bid.

Many antitrust experts and Wall Street analysts wonder if Google's dominant global share of search - starting point for many people on the Web - and its lucrative ad business tied to search will prevent it from joining the Web mega-merger boom.

Analysts say Google appears to have held back from getting involved in the Yahoo-Microsoft deal until it had antitrust clearance for its own US$3.4 billion DoubleClick acquisition, closed a month ago.

The New York Times reported on Wednesday that Microsoft was in talks with News Corp to enlist the media conglomerate's help in funding a joint bid for Yahoo.

The Times also reported Mr Quattrone's role with Google, noting this was his first high-profile assignment since a US judge cleared him of obstruction of justice charges last year.

That case, begun in 2003, was tied to the destruction of e-mail concerning dot-com era IPOs when he was in charge of Credit Suisse's Silicon Valley operations in late 2000.

Over 25 years, Mr Quattrone led teams at Morgan Stanley, Deutsche Bank and Credit Suisse which were responsible for 400 mergers valued at more than US$500 billion. His client list includes many of Silicon Valley's blue-chip tech firms.

In 2003, federal prosecutors accused him of forwarding an e-mail to colleagues in December 2000 suggesting that it was 'time to clean up those files.'

He spent years fighting to clear his name in court. His first trial on obstruction charges ended in a hung jury. He was convicted in a second trial but an appeals court overturned the conviction.