Exxon Mobil, the world's largest publicly traded oil company, reported on Thursday that second-quarter income rose 14 percent, to $11.68 billion, the highest-ever for an American company, according to The New York Times.

Net income of $2.22 a share compared with $10.26 billion, or $1.83 a share, in the quarter a year ago. Revenue rose 40 percent, to $138.1 billion, from $98.4 billion in the quarter a year ago.

Like a smaller rival BP earlier this week, Shell profited from an oil price that almost doubled in the second quarter from the year earlier, but a 13 percent drop from a record on July 11 raised some concern among investors about whether oil companies can keep up the pace of earnings growth. BP said earlier this week that higher oil prices have started to affect consumer demand for gasoline.

Shell's profit rose to $11.56 billion from $8.67 billion in the period a year ago. BP reported a 28 percent increase in profit earlier this week and the Italian oil company Eni said on Thursday that profit in the second quarter rose 52 percent.

Oil companies are under pressure to find new reserves as their traditional fields age and are face increasing competition from state-run oil companies in Russia and the Middle East. Shell is also looking to make up for production lost in Nigeria, where militants attacked an offshore production vessel in June, and in Russia, where it had to sell its share in the Sakhalin Island oil and natural gas project to state-controlled energy company OAO Gazprom last year.

Oil and gas production fell to 3,126 thousand barrels of oil equivalent a day from 3,178 thousand barrels.

Shell's chief executive Jeroen van der Veer pledged to continue investing to spur growth. "Shell is making substantial, targeted investments to grow the company for shareholders and help ensure that energy markets remain well supplied," Mr. van der Veer said in a statement Thursday.

The company agreed two weeks ago to spend about $5.9 billion to buy Duvernay Oil Corporation of Canada to increase its gas production from tough rock formations and is in talks with Iraq about some service contracts.