General Motors said it sold 2.42 million new vehicles worldwide the first quarter, putting it behind Volkswagen Group’s 2.49 million, reported April 17, as the two battle top dog Toyota Motor to be the world’s biggest car company, measured by sales.

Toyota says it will report global sales Thursday. A year ago, it reported 2.58 million worldwide sales the first quarter, so a similar performance this year would keep Toyota No. 1. .

In the U.S. automakers all report sales monthly, and do so on the same day, which usually is the first business day after the end of the previous month. U.S. sales for April are due May 1.

Global counts are more cumbersome and take longer. In some cases, the tallies include both retail sales, to individual and commercial buyers, and wholesale sales to dealers. GM and VW both say theirs are strictly retail.

In the short run, the difference could matter. A car company anxious about its global ranking could accelerate shipments to dealers to boost the count, then later offer dealers discounts to help sell the overstock.

But even when the count is retail, totals could be inflated by an automaker using vigorous incentives during the sales period, knowing it needed to sell a certain number of vehicles to hit the target it wanted.

And a company simply can lie. GM’s Cadillac brand, it admitted later, did that in December 1998 so it could steal past archrival Ford Motor’s Lincoln brand. Lincoln had prepared ads anticipating it would outsell Cadillac, and those had to be scrapped.

Worldwide sales in the first quarter, GM said, were up 2% from a year earlier, on strength in China and North America, and improvement in Europe, a more-or-less black hole for sales and earnings for several years as the continent struggles with a sour economy.

“The momentum our brands are building in China, the U.S. and Western Europe more than offset difficult conditions in some other large markets like Russia and Brazil,” said GM CEO Mary Barra.

Highlights:

•Cadillac, down 6.1% in the U.S. the first quarter, was up 2.5% globally, driven by a 23% increase in China sales.

•European brands Opel and Vauxhall sales increased a bit faster than the European region’s growth.

•Buick, a home-run in the U.S. last year but down 6.5% the first quarter this year, was up 8% globally.

•GMC, the truck-only brand, was up 15%, its best worldwide first quarter sales since 2005.

•Chevrolet deliveries in the United States increased 5.3% in the quarter, slightly under-performing a new-vehicle market up 5.6%, were helped by a 19% increase in crossover SUV sales in the U.S. and a 31% in truck sales. Deliveries in China were up 7%.

Salients of the VW Group report earlier this month:

•VW brand was down 1.3% worldwide.

•Audi premium brand was up 6.1%.

•Porsche roared, up 32.2%.

VW was less optimistic than GM was.

“There is no guarantee this will be a successful year,” VW Group’s board member responsible for sales, Christian Klingler, said. “We saw positive momentum in Western Europe. However, uncertainty – sometimes significant – continues to prevail on markets in Central and Eastern Europe as well as South America”, Klingler said at the time of the sales report.