Exxon Mobil Corporation reported the fifth-largest quarterly net income in American history and Royal Dutch/Shell Group’s first-quarter profit jumped 28% as unprecedented demand lifted energy and chemicals prices.

Profit at Exxon Mobil jumped 44% to $7.86 billion, or $1.22 a share, from $5.44 billion, or 83 cents, a year earlier, the Irving, Texas-based company said yesterday in a statement. Shell said its earnings excluding gains in the value of oil in storage rose to $5.55 billion from $4.33 billion.

Oil companies are reaping record profits as expanding economies in Asia and North America spur demand gains that are outpacing growth in supplies. Crude-oil and gasoline futures reached record highs this month in New York.

“There’s been a huge increase in demand, especially if you look at China and India, where the economies are expanding so rapidly,” said John Leiviska, who helps oversee $17 billion, including Exxon Mobil debt, at Advantus Capital Management in St. Paul, Minn. “Demand is rising in places where they’re trying to enjoy a lifestyle like we have in the West.”

The trend of rising prices, he said, shows no signs of abating. “There are not a lot of easy opportunities remaining to increase supply,” Mr. Leiviska said.

Peter Voser, finance chief at Shell, Europe’s second-largest oil company, told investors on a conference call that he expects oil prices to remain high through the end of this year.

Global oil consumption rose by 2.6% in the first quarter, exceeding a 2.2% gain in production, according to the International Energy Agency in Paris.

Combined net income at the four biggest oil companies that have reported first-quarter results rose 39% from a year earlier to $21.8 billion. Those companies are Exxon Mobil, London-based BP Plc, Shell, and Houston-based ConocoPhillips. The no. 2 American oil company, Chevron Texaco Corporation, is scheduled to report earnings today.

Exxon Mobil’s first-quarter revenue rose 21% to $82.1 billion, more than the full-year economic output of Egypt or Pakistan.

The chief executive, Lee Raymond, 66, is expanding oil production in Africa and building new chemical plants in Asia as growing economies burn more fuel and consume more plastic.

He’s also using windfall profits for stock buybacks. Exxon Mobil said it plans to buy back $3.5 billion of its shares in the second quarter, up from $2.5 billion in the first quarter.

Oil and gas earnings, which generate two-thirds of Exxon Mobil’s profit, rose 26% to $5.05 billion as higher prices more than made up for a 4.7% drop in production. The company still pumps more oil than every member of OPEC except Saudi Arabia and Iran.

“These guys are making so much money, it’s making my eyes water,” said Joseph Ancona, an analyst at Burns Gustus & Co. in St. Louis. Mr. Ancona, who spoke in an interview Wednesday, has a buy rating on Exxon Mobil shares and doesn’t own any.

Exxon Mobil’s profit excluding a $460 million gain from the sale of a stake in China Petroleum & Chemical Corporation was $1.15 a share, 5 cents lower than the average estimate from 20 analysts surveyed by Thomson Financial.

Shares of Exxon Mobil fell $2.38, or 4.08%, to $56 in New York Stock Exchange composite trading.

Exxon Mobil’s profit from chemicals more than doubled to $1.43 billion. Chemicals generated 18% of net income during the quarter, up from 10% a year earlier. Overseas, the company’s chemicals plants generated more profit than refineries for the first time in two and a half years.

At Shell, based in London and The Hague, near-record prices for diesel and gasoline led to wider profit margins at the company’s refining business. That more than compensated for a drop in oil and gas production.

Shell’s net income including inventory gains rose 42% to $6.67 billion. Yesterday’s report was Shell’s first under International Financial Reporting Standards accounting.

Shell is searching for new oil fields after a January 2004 disclosure that it had overstated reserves for years. The overstatement triggered a criminal probe in America, shareholder lawsuits and the departure of three executives.

Mr. Voser, the Shell finance chief, reiterated a forecast for oil and gas output of 3.5 million to 3.8 million barrels a day this year.

BP on April 26 said its first-quarter profit rose 29% to a record $5.49 billion, excluding a gain in the value of its oil inventories.

ConocoPhillips, the third-largest U.S. oil company, Wednesday said its profit jumped 80% to a record $2.91 billion.

Exxon Mobil’s profit was the company’s biggest ever in a first quarter.

MediaOne Group Incorporated had the biggest profit for any quarter in American history when it earned $26.6 billion in the second quarter of 1998. That included a gain from separation of the company’s cable television and telecommunications businesses, public filings showed. AT&T Corporation acquired MediaOne in 2000.

Ford Motor Company had the second-biggest quarterly profit on American record when it earned $17.6 billion in the first three months of 1998. AT&T’s $11.4 billion profit in the third quarter of 2001 was no. 3, followed by Exxon Mobil’s $8.42 billion profit in the fourth quarter of 2004.

TOP 5 MOST PROFITABLE QUARTERS

1. MediaOne 2Q 1998 $26.6 billion
2. Ford 1Q 1998 $17.6 billion
3. AT&T 3Q 2001 $11.4 billion
4. Exxon Mobil 4Q 2004 $8.42 billion
5. Exxon Mobil 1Q 2005 $7.86 billion