Earnings per share topped Wall Street expectations but the gains largely came after a big stock buyback that reduced the number of outstanding shares by 5 percent.

"Their reliance on share buybacks mutes the earnings per share beat," said Brian Youngberg, energy company analyst at Edward Jones in St Louis. "I'd rather see them give the cash to shareholders in the form of a dividend increase."

First-quarter profit for the world's largest publicly traded oil company totaled $9.5 billion, or $2.12 per share, compared with $9.45 billion, or $2 per share, a year earlier.

Analysts, on average, expected the Irving, Texas, company to report a profit of $2.05 per share.

Total oil and natural gas production declined 3.5 percent to 4.395 million barrels oil equivalent per day from the same quarter a year ago.

Profit in Exxon's exploration and production unit fell about 10 percent to $7 billion, but low natural gas prices in North American led to an 62 percent increase in profit in its chemicals business.

Shares of Exxon fell 0.6 percent to $88.91 in premarket trade.

(Reporting by Anna Driver; Editing by Gerald E. McCormick and Jeffrey Benkoe)