In the competitive spirit of college basketball's annual championship tournament, The Motley Fool brings you Stock Madness 2007! Our writers are making head-to-head arguments for their chosen stocks (but not necessarily investment recommendations -- this is, after all, a game), and you'll pick the winners with your article recommendations and Motley Fool CAPS ratings. Who will win the right to cut down the net? Let's tip things off and find out!

The biggest threat facing ExxonMobil (NYSE:XOM) is The Jinx.

Every good sports fan knows about the Sports Illustrated cover-page jinx. When you see a No. 1-ranked team featured prominently on the cover of SI, you'll often see the team lose a key game soon afterwards. But you may not have realized that there's a financial equivalent to the SI jinx: the rankings of stocks by market capitalization. If you own an index exchange-traded fund such as Vanguard Total Market (AMEX:VTI), you know that XOM is No. 1 on your list of holdings.

If history is any guide, that should have you scared. Former No. 1 General Electric (NYSE:GE) reached the top spot in the aftermath of the technology bubble, but its shares have languished over the past several years. Former tech heavyweights Microsoft (NASDAQ:MSFT) and Cisco Systems (NASDAQ:CSCO), which have both occupied the top spot in market capitalization, are well off their historical highs even as the overall market has recovered from much of its losses.

Despite superstitious worries, though, ExxonMobil has been running full throttle for several years now. In addition to paying a sizable dividend, the stock is up roughly 70% over the past five years, as rising oil prices have given the company the largest profits of any business in history. ExxonMobil's record-setting profits are not solely a function of sheer size, though -- the company is vastly more profitable on a relative basis than its Big Oil peers, including Chevron (NYSE:CVX) and BP (NYSE:BP).

ExxonMobil

Chevron

BP

5-year average return on equity

27.2%

21.8%

21.5%

5-year net profit margin

9.6%

6.7%

7.6%
Data provided by Capital IQ, a division of Standard & Poor's.

Meanwhile, the company keeps pushing to improve stock returns by finding new reserves. That's the kind of drive you expect to see in a champion. Despite increasing political pressure from Congress, the community members at Motley Fool CAPS agree that these favorable conditions for ExxonMobil are likely to continue into the future, as nearly seven of every eight players in our stock-rating database have chosen XOM to outperform the overall stock market.

Even with the pressure of being No. 1, there's good reason to think that ExxonMobil can overcome the power of the market-cap jinx and maintain its position atop the list of the largest companies. With energy currently enjoying its day in the sun, ExxonMobil's dominant position will ensure it a prominent place among market leaders for years to come.

If you think ExxonMobil will keep lighting a fire under your portfolio returns, push it through to the next round by following this link to Motley Fool CAPS and ranking the stock "outperform." If not, give it an "underperform." Later this week, we'll count up your votes to determine which stocks will advance one step closer to the title.

Click Sasol to read the opposing entry in this contest.

Click here to read all of the other articles in the tourney.

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Foolish financial editor Dan Caplinger doesn't directly own shares of XOM, although he has several index funds that count it as their No. 1 holding. He does own shares of BP. The Fool's disclosure policy is never maddening.