Exxon Mobil Corp. stock on Wednesday neared $100 per share, the continuation of a rally fueled by investor expectations that the world's largest publicly traded oil company would return more cash to shareholders in coming months.

"They maintained the quarterly share buyback after two quarters of reductions," said John White, analyst at Houston-based oil and gas investment firm Triple Double Advisors. "That's giving investors some confidence about bigger buybacks."

Another factor buoying the Irving, Texas company's shares is the disclosure on Nov. 14 that billionaire investor Warren Buffett's Berkshire Hathaway Inc. had bought 40.1 million Exxon shares, said White.

Shares of Exxon closed up nearly 3 percent at $99.54 on Wednesday, surpassing the previous all-time closing high of $98.87 reached earlier this week.

Since reporting its third-quarter results on Oct. 31, Exxon shares have risen 11 percent, outperforming a 5 percent decline in the SIG oil and gas company index.

At that time, Exxon indicated its capital expenditures may subside next year after planned spending of $41 billion this year, a move seen freeing up more cash for shareholders. The company also said it expects to spend $3 billion on share repurchases this quarter, an amount that equaled those made in the third quarter.