In a bid to remain independent, Yahoo plans to reject Microsoft Corp.’s unsolicited takeover offer, according to reports on the Wall Street Journal’s web site.

Quoting sources familiar with the situation, the Journal reports that Yahoo’s board feels the offer of $31 per share “massively undervalues” the company. A letter spelling out the position is expected to be sent Monday. Yahoo also expressed concern that Microsoft’s offer does not account for risks to Yahoo should the deal be overturned by regulators.

The Journal source said the company would be unwilling to consider an offer below $40 per share, which would represent a $12 billion increase over Microsoft’s original $44.6 billion bid. It is unclear if Microsoft would be willing to increase its bid by such a significant amount.

The two companies have been in discussions about an alliance or merger for more than a year. Yahoo has long hoped to remain independent, believing it can reverse its fortunes and lift its flagging stock price.

In the summer of 2007, investors believed it was possible as well. Yahoo co-founder Jerry Yang replaced Terry Semel as CEO and announced he would unveil a new strategic plan for the company within 100 days.

“There will be no sacred cows and we need to move quickly,” he said. But, after the 100 days – and then some – passed, investor patience wore thin, driving the stock lower.

In late January, the slumping Internet pioneer reported a fifth-consecutive quarter of lower profits and warned of “headwinds” for 2008. Yahoo’s battered stock fell to a four-year low, below the $20 per share level, and Microsoft pounced.

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