Automakers posted their weakest U.S. August sales in 27 years, underscoring uncertainty about the strength of the recovery in the world's largest economy.

Sales dropped 21 percent from the government incentive-fueled boom a year ago. Monthly auto sales data represents one of the first and broadest-based snapshots of consumer demand.

The hesitation by the consumers to spend their hard-earned money continues, said TrueCar.com analyst Jesse Toprak.

On an annualized basis, the sales rate fell slightly from July and was well below what most analysts had expected by now, 18 months after sales hit bottom.

The U.S. sales figures were broadly in line with the cautious expectations of analysts and came as vehicle sales declined in Western Europe as government incentives ended in some countries.

Taken together, the results contributed to concerns that private consumption was faltering or stalled in the mature markets major automakers and established parts suppliers rely on for the largest share of their sales.

Major automakers posted double-digit sales declines in the U.S. market, led by Toyota Motor Corp <7203.T> and Honda Motor Co <7267.T>, which saw results plunge by a third from the subsidy-fueled gains of August 2009.

The U.S. auto sales rate of 11.47 million vehicles was down sharply from the 14 million-plus rate in August 2009 when the U.S. government's cash for clunkers sales incentives touched off a short-lived boom.

In general, automakers had been expecting the industry to sell 11.5 million to 12 million vehicles in the United States this year.

General Motors Co , which is readying a stock offering intended to reduce the U.S. government's majority stake, posted a 25 percent sales drop for August.

Ford Motor Co reported an 11 percent sales decline, while Nissan Motor Co <7201.T> posted a sales drop of 27 percent. Toyota sales were down 34 percent; Honda dropped 33 percent.

Chrysler, now operating under the control of Fiat SpA , posted a 7 percent sales gain. The No. 3 U.S. automaker has relied more heavily than its rivals on less-profitable fleet operators, led by car rental agencies.

The risk of a reversal in the U.S. economic recovery is a potential threat to GM's plans for an initial public offering expected to reduce the U.S. Treasury's nearly 61 percent ownership stake.

CRAWL, STAGGER, REPEAT

GM sales chief Don Johnson said the automaker expected that American consumers would remain cautious given a weak job market but that the industry would continue a slow recovery from the 10.4 million vehicle sales of 2009.

We still see a low risk of any double-dip recession unless there's some unforeseen shock to the system, Johnson said on a conference call.

Paul Ballew, chief economist at U.S. insurer Nationwide and a former GM and Fed economist, said the August U.S. auto sales figures confirmed an exceptionally slow recovery under way.

The way we are describing it is as a crawl-stagger-crawl recovery, Ballew said. Vehicle sales are very much in a line with what we have seen with retail sales and a hesitancy that is out there with consumers.

Jeff Schuster, director of global forecasting for J.D. Power and Associates, said the August U.S. sales results pointed toward a flat-lining for the world's most lucrative vehicle market and second-largest by volume behind China.

The economy is underperforming expectations, but pieces of it are moving in the right direction, he said.

In one sign of a caution, Ford said it expected to build 570,000 vehicles in the fourth quarter, unchanged from its third-quarter production forecast.

That forecast bucked expectations that fourth quarter output would move higher. Ford said the cautious outlook reflected both the expected pace of industry-wide sales and the need to shut down lines to prepare for the launch of new vehicles, including a new Focus sedan coming in 2011.

SILVER LINING: MORE TRUCKS SOLD

The downturn in U.S. auto sales in August extended to the brands that have outperformed and taken market share from rivals amid the recent downturn.

Sales for Hyundai Motor Co <005380.KS> and affiliate Kia were down almost 15 percent on a combined basis. U.S. sales for the Subaru brand dropped 23 percent.

Despite the weak overall sales, automakers were helped in August by a shift toward more profitable sales of larger vehicles, the full-size pickup trucks and SUVs that American drivers had pulled back from during the recession.

Light trucks accounted for almost half of overall vehicle sales in August, up from 42 percent a year earlier.

The pickup truck and SUV market are coming back at a higher rate than we and the rest of the industry had expected, said Bob Carter, the U.S. sales chief for Toyota.

Meanwhile, car sales in France, Spain and Italy fell, as government-funded incentives to spur sales of newer and more fuel-efficient models are fading or have run out.

A bright spot for August was sustained growth in some of the largest emerging markets. Sales in India by the top Indian automakers jumped 20 to 30 percent during the month. Industry-wide sales in Brazil were up 3.5 percent.

In China, the world's biggest auto market by volume, passenger car sales jumped almost 60 percent for the month, a sharp improvement from the sales rise in July.

But runaway growth has been tapering in the world's No. 2 economy since the second quarter as the government tries to stop the economy from overheating.

China's car sales rose to 977,300 in August, according to a government-affiliated research center.

(Additional reporting by Chang-Ran Kim in Tokyo, Helen Massy-Beresford in Paris, Miyoung Kim and Hyunjoo Jin in Seoul, Sonya Dowsett in Madrid, Phil Blenkinsop in Brussels, Antonella Ciancio in Milan, Gianni Montani in Turin and Bharghavi Nagaraju in Bangalore and Bernie Woodall in Detroit; Editing by Matthew Lewis and Erica Billingham)