July 31 (Bloomberg) -- General Motors Corp. probably led U.S. auto sales lower in July as gasoline prices near $3 a gallon sapped demand for the company's light trucks.

Sales at Detroit-based GM, the biggest U.S. automaker, may have fallen 16.5 percent, the average estimate of six analysts in a Bloomberg survey. Ford Motor Co. may say sales fell 7.4 percent, while sales of DaimlerChrysler AG's Chrysler probably rose 2.1 percent.

U.S. automakers depend on trucks for more than 65 percent of sales, making them more vulnerable to rising fuel prices than Toyota Motor Corp. and other Asian automakers focused on cars. Sales of GM's trucks, including sport-utility vehicles and pickups, may have tumbled as much as 22 percent, Credit Suisse analyst Chris Ceraso in New York wrote in a July 26 note.

``It seems truck sales really are going to take a hit, and GM just may not have been aggressive enough with incentives,'' said George Magliano, research director for Global Insight Inc. in New York. Automakers report July sales results tomorrow.

A gallon of U.S. gasoline averaged $2.98 in July, according to American Automobile Association data, up from $2.32 on Jan. 1. Prices have averaged $2.99 in the four months ending today.

``People are accustomed to $3 gas,'' Magliano said. ``They're making decisions accordingly.''

Industrywide sales probably fell 7 percent to an annual rate of 16 million, according to a Bloomberg survey of seven analysts and 22 economists.

Labor Talks

The industry's slide in U.S. sales comes after all three domestic automakers lost money last year. GM cut its loss to $1.98 billion from $10.4 billion in 2005, while Ford lost a record $12.6 billion. Chrysler lost $680 million.

To stem the losses, the automakers are seeking concessions on health care and other expenses in negotiations that began this month with the United Auto Workers for a new four-year contract. The possibility that the talks will lead to cost reductions has helped boost GM shares 6.2 percent this year prior to today while Ford is up 16 percent.

GM today reported an $891 million profit for the second quarter after it boosted revenue in its overseas regions and slashed losses in North America.

July had 24 selling days, one fewer than a year earlier. The analysts' estimates for GM, Ford and Chrysler adjust for the difference. Bloomberg and some automakers use unadjusted percentage comparisons, which would be about 4 points lower.

A July sales decline for GM would follow a 21 percent plunge in June, due in part to a reduction in low-profit transactions with rental-car companies. Overseas sales helped GM top Toyota in global sales last quarter, narrowing the gap with its Japanese rival to 42,000 units for the first half.

Truck Problem

``The trouble at the big automaker is in light trucks,'' Ceraso said of GM. ``Inventories could end the month as much as 20 percent above normal.''

Ford sales probably fell in July as it trimmed more rental- car business and industry totals were ``soft,'' chief sales analyst George Pipas said in an interview.

``The whole pickup segment is lagging this year, and we're a part of that,'' Pipas said. ``We're not likely to see a sustainable rebound for the rest of the year.''

Pipas predicted higher July sales for so-called crossover SUVs such as the Ford Edge. He declined to give any figures.

Ford is clinging to its No. 2 spot in the U.S. The Dearborn, Michigan-based automaker led Toyota by 39,558 vehicles through June, down from a margin of 319,208 a year earlier.

Toyota and Honda Motor Co.'s sales may have risen 6 percent each in July, Ronald Tadross, a Banc of America analyst in New York, said in a July 27 note. The gains probably were led by sales of Toyota's small Yaris car and Honda's Civic sedan.

Chrysler Sales

Chrysler sales probably rose 2.1 percent in July, based on the average estimate in the Bloomberg survey. July may be the last month the Auburn Hills, Michigan-based automaker reports sales as a division of DaimlerChrysler, which is selling the fourth-largest U.S. automaker this quarter to Cerberus Capital Management LP.

A gain of as much as 64 percent in sales of Chrysler cars including the Sebring sedan was offset by an 8 percent decline in light-truck sales, Wachovia Capital Markets LLC analyst Richard Kwas in Baltimore said in a July 24 note. Chrysler depends on truck sales for about 70 percent of its U.S. total.

The automaker also may be aided by a favorable comparison with July 2006, a ``truly weak month for Chrysler,'' said Credit Suisse's Ceraso. Year-earlier Chrysler sales totaled 150,349, compared with 240,146 in July 2005.

Chrysler is the only U.S. automaker to maintain its market share this year through the first six months. Chrysler's share held at 13.5 percent, the same as in the first six months of 2006, as its sales fell 1.5 percent, keeping pace with the industrywide sales decline.

U.S. Market Share

GM's share fell to 23 percent from 24.3 percent, and Ford's fell 1.8 percentage points to 16.6 percent, according to Autodata Corp., a Woodcliff Lake, New Jersey-based company that monitors industry sales.

Toyota boosted its market share in the first six months to 16.1 percent from 14.6 percent. It has raised sales in 24 of the last 25 months.

Ford has said it is seeking to sell its Jaguar and Land Rover divisions, which account for slightly more than 2 percent of the company's sales. It is also exploring a sale of the Volvo unit, responsible for another 4 percent of sales.

GM shares fell 21 cents to $32.40 at 4:22 p.m. in New York Stock Exchange composite trading, and Ford's dropped 23 cents to $8.51. U.S. shares of DaimlerChrysler rose 96 cents to $90.75. Toyota's American depositary receipts slid $1.16 to $120.63.

Bonds, Credit-Default Swaps

GM's 8.375 percent note due July 2033 gained 2.88 cents to 84 cents on the dollar, yielding 10.13 percent, according to Trace, the NASD's bond-price reporting service. Ford's 7.45 percent note due July 2031 rose 3.75 cents to 79.75 cents on the dollar, yielding 9.63 percent, according to Trace.

DaimlerChrysler's 8.5 percent note due January 2031 rose 0.73 cent to 123.67 cents on the dollar, yielding 6.52 percent.

Credit-default swap contracts based on $10 million of GM bonds dropped $79,500 to $618,800, according to CMA Datavision in London. Ford's declined $54,600 to $711,200 and DaimlerChrysler's fell 11,700 euros to 51,500 euros ($70,607).

The contracts are designed to protect bondholders against default. A decline in the price indicates a rise in the perception of a company's credit quality.

The following table provides estimates for car and light- truck sales in the U.S. Estimates for companies are percentage changes from July 2006. Forecasts for the seasonally adjusted annual rate, or SAAR, are in millions of vehicles.

The SAAR average is based on forecasts from seven analysts and a survey of 22 economists. The analysts' estimates are based on daily selling rates and are adjusted to account for July 2007 having 24 selling days, one fewer than July 2006.

Analyst                   GM     Ford     Chrysler    SAAR

Himanshu Patel          -25%      -8%       -3%       15.6
 (JPMorgan)
Chris Ceraso            -21%*     -8%*       4%*      15.8*
 (Credit Suisse)
Jesse Toprak          -18.1%   -10.5%      7.3%        N/A
 (Edmunds.com)
Richard Kwas            -10%      -3%        6%       16.3
 (Wachovia)
Jon Rogers              -14%      -6%       -2%       15.9
 (Citigroup)
Ronald Tadross          -11%      -9%      0.0%       16.3
 (Banc of America)
George Magliano          N/A      N/A       N/A       15.8
 (Global Insight)

Bloomberg Economists     N/A      N/A       N/A       16.0
(average estimate)

AVERAGE:              -16.5%    -7.4%      2.1%       16.0

*Estimate presented as a range. Figure shown here is an average
of the range, rounded to the nearest tenth where appropriate.

To contact the reporter on this story: Greg Bensinger in Southfield, Michigan, at gbensinger1@bloomberg.net

Last Updated: July 31, 2007 16:26 EDT