Exxon's trip from world's most valuable to dog of the Dow

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Oh, how the mighty have fallen.

ExxonMobil, the world's largest oil and gas concern, has seen its stock close in negative territory in 19 of the past 20 sessions. Since scaling to a five-year high of $95.45 in July, it's been all downhill since then as the stock has tumbled 9 percent.

Exxon's steep slide has cost investors in more ways than one. The oil big was once the world's most valuable company in terms of its market capitalization. Now, at $382 billion, Exxon's market capitalization is well behind technology giant Apple, which enjoys a market cap of about $458 billion.

Over the past 20 sessions, the energy giant has become the worst-performing component of the 30 blue-chip stocks that comprise the Dow Jones industrial average.

Exxon's point impact on the Dow over that period is second only to Chevron, the world's second-largest oil company: XOM has shaved approximately 52 points off the Dow while CVX has sliced more than 60 points off the index. Together, Exxon and Chevron accounted for 25 percent of the Dow's 565-point decline over the past 20 sessions.

Although the U.S. is in the midst of an oil and gas renaissance that is transforming energy markets worldwide, that boom is largely dominated by small and midsize companies.

—By CNBC's Javier E. David and Giovanny Moreano.