According to data compiled by Toyota Motor Thailand, the monthly sale figure showed a 3.5 per cent decrease from the same period last year. The June figures are expected to show a fall.
It attributed the fall to the end of the first-car buyer scheme, which drew booking for 1.2 million units. Most of the booked vehicles have been delivered.
Many companies in May witnessed a drop in sales: Toyota, 13 per cent; Mitsubishi, 12 per cent; Mazda, 15 per cent: Nissan, 55 per cent; Chevrolet, 20 per cent; and Ford, 7 per cent.
Witnessing the year-on-year sale increase were Honda, 39 per cent: Isuzu, 10 per cent; and Suzuki, 129 per cent.