Samsung Electronics controlled half of the market for ultra high definition TVs in North America as of December.
According to market researcher DisplaySearch on Sunday, Samsung topped the market with a 48.3 percent share in November and 49.8 percent last month.
Samsung had already emerged as the No. 1 player for UHD TVs in Europe in October.
The world's largest flatscreen TV maker had been left behind in the UHD TV market due to Sony's prior dominance. When it released its first UHD models there in July, Samsung's share stood at 2.5 percent compared to Sony's 82.8 percent. But by December it had turned the tables by occupying 49.8 percent to Sony's 39.9 percent.
Overall, Samsung has been the most popular TV manufacturer in North America for eight straight years. Its share of the total market climbed 2.4 percent last year to 32.3 percent.
American brand Vizio was second with 16.1 percent and LG third with 11.3 percent.