WASHINGTON (MarketWatch) -- Signaling that some businesses have still been spending despite tight credit and a slow economy, the Commerce Department reported Wednesday that new orders for U.S.-made durable goods surged in July, rising 1.3%.

Strong transportation equipment demand boosted the result, Commerce reported. Economists surveyed by MarketWatch had been looking for a gain of 0.2%. Excluding transportation goods, July's new orders rose 0.7%.

Durable goods are big-ticket items designed to last three years or more. As such, new orders are very sensitive to economic expectations and serve as useful leading indicators of growth.

Orders for core capital-equipment goods -- considered the best monthly gauge of business investment -- rose 2.6% in July, following a 1.3% gain in June. Core capital equipment orders exclude aircraft and non-defense goods.

Meanwhile, shipments of these goods -- which are factored directly into the government's calculations of gross domestic product -- rose 0.6% in July, following a 0.4% gain in the prior month.

Exports, special factors support durables

Economists said exports are likely behind the strong durables report.

"The sectors, which last month posted the biggest increases in orders -- machinery and metal -- are usually very export oriented," wrote Harm Bandholz, an economist for UniCredit Markets.

Ian Shepherdson, chief U.S. economist at High Frequency Economics, wrote that the domestic economy remains "very weak indeed," and that companies benefiting from the export boom are likely behind the increase in capital spending.

"The risk must be that in time the combination of slowing global growth and a stronger dollar crimps exports, but for now they are the lifeline," Shepherdson wrote.

Tony Crescenzi, chief bond market strategist for Miller Tabak & Co., wrote that there is "weak" basis for further gains in durable goods orders given the weak U.S. economy, and that the fresh data should "be taken with a grain of salt." Companies are using capital investments to control costs by increasing productivity, he wrote.

"Companies simply have no basis to expand their productive capacity; it is why businesses are cutting payrolls," Crescenzi wrote. "Only if economic growth moves closer to the economy's productive capacity will companies feel comfortable boosting their capacity, otherwise they will be stuck with unwanted and costly excess capacity."

He added that the durables report was also boosted by special factors such as price increases for metals and temporary capital spending incentives from Washington.

Details

New orders for durable goods in June were revised to an increase of 1.3% from a prior estimate of 0.8% growth.

Also for July, shipments of durable goods rose 2.5%, picking up from an increase of 0.9% in the prior month.

Excluding transportation goods, July shipments rose 2%.

Both inventories and unfilled orders rose 0.8% last month, according to the Commerce Department.