Toyota has forecast its 2012 sales will jump 22% to 9.7 million vehicles.
GM, which briefly regained the crown after Toyota's supplies were shattered by the 2011 Japanese quake and tsunami, nonetheless remains at number two worldwide.
The company said its share of the global auto market fell 0.4 points to 11.9%.
GM's international operations -- Asia-Pacific, Africa and the Middle East -- posted the biggest gains, with sales up 10.1% at 3.6 million while its share was flat at 9.5%.
Sales fell 8.2% in Europe to 1.6 million vehicles, while GM's share narrowed by 0.2 points to 8.5%.
North American sales rose 3.2% to just over three million, though GM's share of its home market fell 1.5 points to 16.9%.
Sales in South America shrank 1.9% to just over a million vehicles, while GM's share of the region fell 0.8 points to 18 percent.
Rival Volkswagen, which aspires to be the world's biggest automaker by 2018, reported an 11% increase in 2012 sales to 9.07 million on Sunday.
Copyright Agence France-Presse, 2013