SAN FRANCISCO, US - MICROSOFT is evaluating its bid for Yahoo because the Internet company may have lost value since it made its offer, a person familiar with the matter said.

The news, sent Yahoo shares down more than 5 per cent in extended trade.

A Yahoo spokesman declined to comment. Microsoft was not immediately available for comment.

Yahoo has rejected Microsoft's offer, made on Jan 31, saying it 'substantially undervalues' the company.

The bid initially valued Yahoo at US$44.6 billion (S$61.6 billion), but is currently worth about US$42 billion.

Microsoft has been repeatedly trying to engage Yahoo's board in discussions, the person said. But the market has deteriorated and changes in Yahoo's business may have dragged down its value below what it was when Microsoft made its bid, the person said on Friday. -- REUTERS