The figure was fueled by sales increases in emerging markets outside the United States.
Toyota, which beat GM in global vehicle sales for the first half of the year, is to release its third-quarter results on Monday.
Toyota reported selling 4.72 million vehicles during the first half of the year compared with GM's 4.67 million.
GM still led Toyota in vehicles produced worldwide during the first half of the year. Toyota and its group companies produced 4.71 million vehicles in the first half, inching up to GM's 4.75 million vehicles.
GM has held the title of world's biggest automaker for 76 years.