Investors have been buzzing about speculation that AT&T ( T - Get Report) is bailing on its partnership with Yahoo! ( YHOO), but the truth is harder to discern.

On Friday, The Wall Street Journal reported that AT&T was considering scaling back the alliance with Yahoo!, which is set to expire in April 2008. The deal, which was signed in 2001, provides Yahoo! with a percentage of the revenue from DSL subscriptions, and losing it could cost the company $200 million to $250 million in revenue.

But later Friday, Yahoo! announced that the Journal's story was based on "rumor and speculation," saying "AT&T and Yahoo!'s ongoing partnership is rooted in the open and ongoing dialog we maintain about future opportunities."

Investors have a lot at stake in deciphering where the two companies stand. Not only does the AT&T partnership provide Yahoo! with high-margin revenue, the Internet giant also has similar deals with Verizon ( VZ - Get Report), British Telecom ( BT) and Rogers Communications ( RG).

That brings total revenue from deals with communications companies closer to about $350 million a year, Stifel Nicolaus analyst Scott Devitt pointed out in a research note on Friday. Stifel makes a market in Yahoo! shares.

AT&T's potential reneging on the Yahoo! deal could lead other telecom companies to reconsider their own arrangements. Yahoo! also would lose traffic to its site in the event that these deals are scrapped, because communications companies often direct Web surfers who use their services to access the Internet to Yahoo!'s site.

But if it's business as usual, as Yahoo! suggests, investors may have found a good opportunity to pick up the stock at a slight discount. Yahoo! shares closed Friday down 5%, but have rallied 20% since the beginning of the year as Panama -- Yahoo!'s highly anticipated new system of ranking ads -- has met with stellar reviews, providing many investors with renewed optimism.

A selloff on unfounded rumors would provide investors a chance to buy in on a stock with considerable momentum.

It may be easier to judge the veracity of Friday's developments by turning to AT&T. And there, what's notable is the response by AT&T itself -- and by its shareholders.

After all, a simple denunciation by AT&T of the report is all it would have taken to bail out Yahoo! Instead, AT&T declined to comment on the report, according to The Associated Press.

And even a second press release put out even later on Friday -- bearing all the marks of face-saving cajoling on the part of Yahoo! -- seems to confirm rather than deny the report.

"Great partnerships must continuously work together to adapt to the changing market conditions and changing strategies," the press release quotes AT&T COO Randall Stephenson as saying. "We consider our partnership with Yahoo! a great partnership and want to continue building our complementary skills and expertise."

In other words, the alliance may hobble along, but a serious change in its terms is in the works.

Moreover, while the news jolted Yahoo!'s stock price, AT&T's stayed unmoved. This signals that the market believes AT&T will be just fine selling DSL connections without Yahoo!'s help, and again underscores that Yahoo! now needs AT&T more than the other way around.

In fact, far from denouncing the Journal report, it hardly would be surprising if AT&T played a role in fostering it. Earlier this week, Google ( GOOG - Get Report) CEO Eric Schmidt mused about his experience negotiating with old-media companies, for which leaking to the press to pressure the other party was almost protocol.

"The source of the comments for the article likely came from AT&T (could be negotiating tactic)," Merrill Lynch analyst Justin Post wrote in a research note on Monday morning. Merrill makes a market in shares of Yahoo!.

AT&T has every reason to re-evaluate the terms of its deal with Yahoo! and push harshly for concessions. A lot has changed since 2001, when the deal was originally signed. Then, Yahoo!'s popular, user-friendly services were a big help in persuading Web surfers to pay extra for high-speed instead of dial-up service.

Now, broadband connections have instead become the de facto standard instead.

And with the explosion of the lucrative paid-search market, AT&T well may be able to receive money rather than give it. AT&T brings traffic to Yahoo!, and in search-marketing, more traffic leads to more click-throughs and more revenue. Deep-pocketed Google, for example, revels in pointing out that it paid $3 billion to its partners last year, many of which drive traffic and search volume for the company.

Of course, pulling the plug on Yahoo! and taking its business elsewhere would come at a cost to AT&T. Many of its customers are used to Yahoo!'s service, and the companies have invested considerably in developing products together.

The best outcome for AT&T would be a situation in which it continues doing business with Yahoo!, but on more generous terms. Leaks in the press threatening a walkout -- and jolting Yahoo!'s stock in the process -- would be a great way to re-establish the roles.

By publicly talking up how cozy its relationship is with AT&T, Yahoo! may have inadvertently put even more on the line when it comes to making sure AT&T sticks around. AT&T will end the day with more leverage, because a breakup now would seem even more of a black eye for Yahoo!

Some sort of partnership between Yahoo! and AT&T likely will limp along. But from now on, AT&T is in the driver's seat. And while Yahoo! probably will make sure everything appears to be humming along on the surface, it will be impossible to hide the new order as it pertains to the bottom line.