Fueling 93,637 trucks and 264 planes is taking its toll on profits of Sandy Springs-based UPS, the world's largest package carrier.

On Tuesday, the company's stock fell more than 6 percent to $62.26, a five-year low.

Twelve million shares changed hands, more than double the average daily volume of about 5 million shares.

The drop came a day after UPS slashed its earnings estimates, blaming revved up fuel prices.

The company said Monday it expected second-quarter earnings per share of 83 cents to 88 cents, compared to previous estimates of 97 cents to $1.04. A similar earnings warning last quarter was blamed for taking much of Wall Street on a wild, one-day ride.

In the first quarter, UPS's fuel cost was $950 million, a 54 percent increase over the first quarter of 2007.

"We've never experienced or had to manage to this type of fuel expense before," said UPS spokesman Norman Black. "The jumps that we're seeing now are historic."

The resulting effect on its stock is unnerving for investors, who for years benefited from UPS's fairly stable stock price.

Investment firm Standard & Poor's downgraded UPS stock on Tuesday to hold from buy, showing decreased confidence in the package carrier's expected financial results.

UPS's bad news on profits may portend worse times ahead for the broader economy. Package carriers are a barometer of the health of the economy because their shipping volume indicates how other businesses are doing.

"We had thought UPS would benefit from increased investor interest in logistics stocks in advance of an improving economy. It is now our view that that recovery will take longer than we earlier expected," Jim Corridore, air freight industry analyst for Standard & Poor's Equity Research, wrote in a note to investors.

He said he was cutting earnings estimates for UPS "to reflect our view of oil and economic risks."

UPS buys all manner of fuel: jet fuel, diesel and gasoline, as well as liquefied and compressed natural gas and propane for its 1,629 alternative-fuel vehicles. The cost of each of these fuels has increased.

To ease the effects of rising fuel costs on its bottom line, UPS plans to raise the fuel surcharge on air packages to 32.5 percent on July 7, from 28 percent now. The surcharge on ground shipments will go up to 9.5 percent, from 8.5 percent now.

Black said that UPS is finding creative solutions to cut fuel consumption.

With its planes landing at UPS's Louisville air hub, for example, pilots are experimenting with a continuous descent in which they approach the runway at a much faster rate of speed, without needing to brake and then employ gas-guzzling thrusters.

This one change, Black said, saves 40 to 70 gallons per landing.

UPS's package-flow technology designs the most efficient route for each truck, based on package volume and delivery locations.

The routes are planned with "concentric right-hand routes," said Black, "so we don't turn left." That saves on idling time and, therefore, fuel.

While current earnings may disappoint Wall Street, Black said the company is focused on long-term shareholder value.

"We want the investor who recognizes that the long-term future of this company is as bright as any company in the world because of all the trends of e-commerce, globalization, reliance on modern supply chain management, concerns about security and how you get through customs," Black said. "Every trend ... shows a very bright future for UPS."