Yahoo leaders Roy Bostock and Jerry Yang said they're relieved that Microsoft has taken its merger proposal off the table. Will they still feel that way when the markets open Monday and investors' attorneys start calling?The background: Microsoft CEO Steve Ballmer on Saturday publicly revealed that he had withdrawn what, by then, had become an offer to buy out Yahoo for $33.00 per-share, or $47.5 billion.

That would have been a 70% premium over Yahoo's market value prior to Feb. 1, the day Microsoft became a formal suitor.

Ballmer said his decision was prompted by Yahoo CEO Yang's insistence that his company not be bought for less than $37.00 per-share. Ballmer also stated that Yahoo's threat to outsource search advertising to Google complicated things to the point that it made a proxy battle impractical.

This is all good news for the Yahoo universe, according to Yang and chairman Bostock.

"From the beginning of this process, our independent board and our management have been steadfast in our belief that Microsoft's offer undervalued the company and we are pleased that so many of our shareholders joined us in expressing that view," Bostock said in a hopeful statement released by Yahoo within hours of Ballmer's bombshell.

Yang added the following: "With the distraction of Microsoft's unsolicited proposal now behind us, we will be able to focus all of our energies on executing the most important transition in our history so that we can maximize our potential to the benefit of our shareholders, employees, partners and users."

Bostock went so far as to add that Yahoo's "solid" first quarter results prove that the company can get by just fine without Microsoft.

Some Yahoo investors, especially those that have already sued the company for not accepting Ballmer's initial offer to pay a 62% premium for their shares, might beg to differ.

Yahoo last month reported a 9% increase in revenue for the first quarter. But, excluding one-offs like restructuring costs and a windfall from the Alibaba IPO, operating income plunged 18% while net income declined marginally.

Those numbers were so "solid" that Yahoo shares opened lower on April 23, one day after their release.

That's a strong indication that the approximate 50% price gain that Yahoo shares have enjoyed since Feb. 1 is entirely due to the Microsoft offer, and not some Pollyannaish belief among investors that Yahoo, wearing its Panama hat, can claw its way back to into competition with Google.

Yahoo shares should fall back below $20 (let's call that the Ballmer line) by mid-morning on Monday. For anyone counting, that's about $14 billion in market cap about to go poof!