Jan. 2 (Bloomberg) -- Toyota Motor Corp.'s namesake division may declare itself the No. 1 auto brand in the U.S. for 2007. General Motors Corp.'s Chevrolet won't agree.

The dispute pivots on one question: How should sales of Toyota's Scion cars be tallied?

At stake are bragging rights that go with the top-selling line of autos in the U.S. Toyota's count includes Scion, cars that bear no Toyota badges and are marketed separately. By that measure, the Japanese automaker's lead through November sets the stage for a full-year win. Leave Scion out, and Chevy will likely retake the title when results are released tomorrow.

``I don't think for a second that Scion is a Toyota vehicle; it's clearly its own brand,'' said Tom Libby, an analyst for J.D. Power and Associates. ``You might as well count Pontiac vehicles as Chevrolet sales if you think Scion's a Toyota.''

Overtaking Chevrolet, the largest of GM's seven U.S. brands, would mark another triumph for Toyota. The Toyota City, Japan- based automaker passed Ford Motor Co. in the past year to become the No. 2 seller of autos in the U.S. and is threatening to pass GM in global sales.

``We don't consider Scion a part of the Toyota brand,'' said Terry Rhadigan, a GM spokesman for the Chevrolet division. ``On our scoreboard, we're leading.''

Countered Toyota spokesman Xavier Dominicis: ``We've always counted it that way, and it's sold only at Toyota dealerships.''

A 14 percent sales decline through Nov. 30 at Ford's main division put Chevrolet in a position to retake the sales title it won in 2005. The Ford brand trailed the Toyota division, without Scion, by nearly 66,000 units at the end of November.

Different Strokes

J.D. Power, of Westlake Village, California, separates Scion from Toyota in its tallies, as does Ward's Automotive Reports, of Southfield, Michigan. Another compiler of sales statistics, Autodata Corp., includes Scion in its Toyota-brand total.

Through November, the Toyota-Chevrolet race was tight enough to hinge on Scion. Including Scion, Toyota sold 2,101,804 cars and light trucks, for a 35,524-unit advantage. Without Scion's 121,237 vehicles, Chevrolet would be on top by 85,713.

Toyota says that unlike the luxury Lexus division, whose vehicles are sold at distinct dealerships and tallied separately, Scion was always intended to be a branch of the main brand. The automaker adopted that standard when the cars made their U.S. debut in 2003. Scion's three models are the xB, xD and tC.

Remembering Geo

Counting Scions as Toyotas echoes an approach Chevrolet used when it tallied the Geo line of cars as its own, said David Lucas, an analyst with Autodata in Woodcliff Lake, New Jersey. He said his company registers Scion sales for Toyota because the automaker insists they are part of its main brand.

At its peak of 325,143 units in 1990, the Geo line made up 13 percent of Chevrolet's U.S. sales, according to Autodata. In comparison, Scion sales accounted for 7.8 percent of the Toyota division in 2006. In 1990, Toyota trailed Chevrolet by 1.6 million vehicles.

Rhadigan said GM made it clear Geos were aligned with Chevrolet because they bore a diminutive Chevy bowtie in the middle of the vehicles' front-end logo, designed to look like a globe, whereas Scion vehicles aren't identified as being part of Toyota. Geos were sold exclusively at Chevrolet dealerships before the line was suspended following the 1997 model year.

U.S. sales for Toyota may have dropped 4 percent last month due in part to a 6 percent decline in truck sales, said Chicago- based Lehman Brothers analyst Brian Johnson in a note today. He expects GM to report a 6 percent decline.

Toyota trailed GM in global sales by about 10,000 units at the end of 2007's third quarter, after leading in the first half by 39,000. Global sales results will be released later this month.

GM fell 48 cents to $24.41 at 4:02 p.m. in New York Stock Exchange composite trading, its sixth straight decline and its lowest since May 2006. Toyota's American depositary receipts rose 29 cents to $106.46.

To contact the reporter on this story: Greg Bensinger in New York at gbensinger1@bloomberg.net

Last Updated: January 2, 2008 16:11 EST