Normally, investors study earnings reports for their numbers. Not so with Yahoo. When the internet veteran delivers its first-quarter earnings after the stock markets close today, Wall Street will be watching instead the latest episode in the hostile-takeover soap opera starring Yahoo and Microsoft.

Business headlines on Yahoo's earnings read like a program summary out of TV Guide:

"Yahoo is making its last stand to repel its suitor, a stand that must turn the tables or else it may have to surrender."

Such tension, common enough in sports and politics, is rare in business. Financial writers have to make hay while they can.

Analysts, too, are talking plot twists.

"The most important elements of the earnings announcement will center on Yahoo's defense against the hostile-takeover bid announced by Microsoft," Stifel Nicolaus analyst George Askew said.

Needham's Mark May, meanwhile, is expecting no surprises, but added that even earnings in line with expectations "will tilt negotiating power in the Microsoft takeover bid toward Yahoo."

So for Yahoo, the drama is trumping the numbers. But this is Wall Street, where the numbers get the final say—and the numbers say that even a blowout quarter for Yahoo isn't going to have any lasting effect on its stock price.

There is, however, really only one number driving Yahoo's stock these days, and it has nothing to do with profits or revenue. It's the $31 a share that Microsoft bid for Yahoo back in February. That offer was so lavish—a 62 percent premium above Yahoo's actual market value—that Yahoo would have to perform a miraculous turnaround to deserve it.

Yahoo's stock has been trading around $28 and $29 a share, pricing in a chance the deal will fall through. But arbitrageurs betting that Microsoft will prevail haven't tolerated much more of a deviation than that. And that makes an independent Yahoo absurdly expensive.

Wall Street is expecting Yahoo to earn 44 cents this year and 55 cents a share next year. That means Yahoo is trading at 52 times its estimated 2008 earnings. Google, by contrast, is trading at 22 times its earnings next year—even after Google's 20 percent rally since its strong earnings last week.

To fall in line with Google's valuation, Yahoo would have to earn $1.30 a share next year—more than double what Wall Street is expecting.

Yet Yahoo has little choice but to convince Wall Street it's worth $31 a share on its own. Last month, executives made its case with a presentation to investors arguing that the Street's estimates were significantly wrong. Yahoo said revenue would grow 25 percent next year to $7.1 billion. Analysts are looking for only $6.4 billion.

Few were persuaded by Yahoo's optimism—the stock didn't budge, and many analysts maintain a "hold" rating on the stock. Yahoo is actually doing a good job of turning the company around, but its value is nowhere near what Microsoft can guarantee to pay.

Jeffrey Lindsay, a Sanford Bernstein analyst, said Yahoo will be pulling out all the stops to deliver strong first-quarter numbers. If so, that could trigger a short rally, but the stock is likely to revert to its pre-earnings range.

On Wednesday, Microsoft will report earnings—and surely rebut any bullish message from Yahoo. Microsoft has already said it will turn up the heat on the takeover if Yahoo doesn't acquiesce by Saturday.

So Yahoo's best hope is to offer just enough leverage to push Microsoft into a higher bid. That would almost certainly drive up Yahoo's stock. But the catch is, a disappointing report would give Microsoft reason to lower its bid.

That would be bad for Yahoo's investors. But not as bad as if Yahoo got what it wants most: If the merger falls through, it will wreak havoc on Yahoo's stock. Factor out Microsoft's premium and you're left with a company that's worth a lot less than its stock is trading for right now.