Tesla is expected to have sold 16,000 of its Model 3 cars in the US by the end of July.
July sales of the BMW 2, 3, 4 and 6 Series are expected to reach 12,811 at the end of the month.
Mercedes are expected to sell 12,811 CLA, CLS and E-Class vehicles.
That gives Tesla a 23% share of the small and midsize luxury car market in July, ahead of 17% each for BMW and Mercedes.
In Q1, Tesla produced more than 53,000 cars with production of the Model 3 – at 28,578 cars – more than double the combined production of the Model S and X at 24,671 cars.