One challenge in translating demand into profits lies in the figures for individual models.

Tesla said it delivered 79,600 Model 3 sedans in the quarter, an increase of 2.6 percent from the second quarter. But deliveries of its larger, more established offerings — the Model S and the Model X — totaled 17,400, a decline of 250. Analysts say that is a problem for Tesla, since those vehicles often sell for $90,000 and produce far more profit than the Model 3, which sells for as little as $39,000.

Jeffrey Osborne of Cowen & Company said in a recent note to clients that unless Tesla cut costs enough to make money on the least expensive version of the Model 3, “margins are likely to continue to be under pressure and we don’t see sustainable profitability in the near to midterm.” He added that Cowen saw “a lot more that can go wrong than can go right.”

Tesla lost $408 million in the second quarter even as it reported record deliveries and a substantial increase in revenue. Its third-quarter financial report is due in the weeks ahead.

So far this year, Tesla has delivered about 255,000 cars. To reach the low end of the range it has forecast for the year — 360,000 to 400,000 — it will need to sell more than 100,000 in the fourth quarter, only a slight increase from the third quarter but a milestone it has not yet achieved.

Since introducing the Model S in 2012, Tesla has become one of the top producers of luxury cars in the United States, rivaling more established brands like BMW and Mercedes-Benz. But the company has yet to turn an annual profit since its founding in 2003. And automakers including Porsche, Volvo and Audi are rolling out competing electric cars at a time when Tesla is at least a year away from the next addition to its lineup, the Model Y, a roomier version of the Model 3.