Schlumberger's fourth-quarter net income jumped 31 percent, the company reported Friday, as demand for oilfield services surged around the world along with the price of energy.

Oil prices have moved consistently higher since last summer. A barrel of oil now costs more than $90.

The energy industry, after slumping during the recession, is aggressively bumping up production to meet demand and major oil producers need companies Schlumberger to manage drill sites across the globe.

The company's shares have been climbing since last summer as well, and before the market opened Friday, the stock rose nearly 2 percent to $86.80.

Schlumberger has had to grow with major producers and last year spent $11 billion to acquire Smith International Inc.

It was the time that Smith's operations were reflected over an entire quarter and during the past three months, the company contributed revenue of $2.49 billion and pretax operating income of $275 million.

Schlumberger Ltd., based in Houston, earned $1.04 billion, or 76 cents per share, for the final three months of the year. That compares with $795 million, or 65 cents per share, in the year-ago period. Revenue increased 58 percent at $9.07 billion.

Analysts had expected a bigger profit, and Delta shares fell 58 cents, or 4.6 percent, to $12.17 in morning trading. Shares of other airlines were lower as well.

Delta earned 2 cents per share for the fourth quarter. Not counting special items it would have earned 19 cents per share. Analysts surveyed by FactSet expected 27 cents per share. A year earlier it lost $25 million, or 3 cents per share. Delta said many analysts didn't include the impact of the late-December storms.

Earlier this month, Delta said the snow storms would cut its fourth-quarter profit by $45 million after it canceled some 4,000 flights.

Revenue rose 14 percent to $7.79 billion, more than analysts expected.

During 2010, airlines including Delta, benefited as passengers -- especially business travelers -- returned to flying as the economy improved. Delta's revenue for each passenger flown one mile rose 8 percent during the fourth quarter. Delta's operating costs for each seat flown one mile rose by 2 percent. They would have fallen 2 percent if not for fuel and special items. Its fuel bill alone rose 13 percent to $1.93 billion for the quarter.

The results fell short of analysts' estimates, sending Citi's stock down 5.5 percent to $4.85 in heavy trading. Other banks also fell. Citi earned 4 cents per share, below the 7 cents analysts surveyed by FactSet were expecting.

The results were an improvement compared to the loss of $7.6 billion, or 33 cents a share, reported for the same quarter of last year. Revenue was $18.4 billion compared to $5.4 billion a year earlier.

For the year, Citigroup earned $10.6 billion on revenue of $86.6 billion. It's the first full year of profits for the bank since 2007.

More of Citigroup's customers were able to meet payments on credit cards and home loans. Its credit losses of $6.9 billion were down $805 million from the previous quarter, or 11 percent, marking the sixth consecutive quarter of declines. The reduced losses allowed the bank to release $2.3 billion from reserves it set aside for bad loans.

As expectations of an economic recovery have increased, the New York bank set aside $4.8 billion for future losses, its lowest level since the second quarter of 2007.

The aircraft maker reported Tuesday that it expects to deliver its new 787 jet between July and September.

Boeing is up 3 percent, leading the 30 companies that make up the Dow Jones industrial average. Stocks had been trading lower in the morning with Apple Inc. and Citigroup weighing on indexes. Apple fell 3.3 percent after saying that CEO Steve Jobs was taking another medical leave. The company will also report earnings after the stock market closes, along with IBM Corp. Citigroup fell 5.3 percent after reporting weak earnings.

As analysts and investors brace for earnings reports from more than a dozen major U.S. manufacturers over the next two weeks, they will eye revenue growth as one of the surest signs of health for the industrial sector over the next year.

Sales growth will be critical to profits this year, since major companies including General Electric Co, United Technologies Corp and 3M Co will likely face rising costs of everything from copper to payroll, which they had slashed going into the recession.

Cost management will matter if the sector is to continue its strong run on Wall Street. Standard & Poor's industrials group rose about 20 percent over the past year, the second-biggest gain in the broad S&P 500 index after the S&P consumer discretionary group which rose almost 26 percent.

"From a top-line, revenue side, we're going to see some modest expansion there," said Peter Klein, senior portfolio manager at Fifth Third Asset Management, in Cleveland, Ohio. "This is what I'm sort of tuning my ear to hear. And if we don't hear it, then maybe some of this ebullience that we've seen in the industrials since this summer will flatten out."