Tesla on Wednesday said profits in the past quarter more than doubled as the electric car giant forecast deliveries hitting 500,000 this year.

Net profit in the quarter rose to $331 million, up from $143 million a year earlier, as revenue rose nearly 40 percent to $8.7 billion.

Tesla's share price was up more than three percent in after-hours trade on the results.

"We continue to see growing interest in our cars, storage and solar products and remain focused on cost-efficiency while growing capacity as quickly as possible," Tesla said in a letter to shareholders.

With its hot-selling electric cars, Tesla has stood out among auto industry peers and as it invests in building up its lineup with more affordable prices than in the past.

It delivered 139,000 vehicles in the past quarter, amid strong growth in its Model 3 car, the least expensive in its lineup.

"We are increasingly focused on our next phase of growth," the letter said.

"Our most recent capacity expansion investments are now stabilizing with Model 3 in Shanghai achieving its designed production rate and Model Y in Fremont (California) expected to reach capacity-level production soon."

A man looks at a Tesla Model 3 in a Tesla showroom in Beijing on October 21; the electric car giant reported a doubling of profits on robust sales growth
A man looks at a Tesla Model 3 in a Tesla showroom in Beijing on October 21; the electric car giant reported a doubling of profits on robust sales growth AFP / GREG BAKER

Tesla has also broken ground for a new manufacturing facility in Germany.

"Tesla used to be considered the up-and-coming automaker, but with half a million units of planned annual production and a globally expanding presence it's safe to say that the company is well out of rookie territory," said auto analyst Jessica Caldwell of Edmunds.

"If it continues on this same path, it seems that Tesla will become a fairly mainstream automaker before the mid point of this decade."

Caldwell said that if Tesla is able to deliver on its promise for an electric car priced at $25,000, "hat could be a gamechanger for not just the company, but the entire industry."

Tesla has reported progress in what it claims to be a fully self-driving auto software system, saying an update is expected this month.

"Our Autopilot team has been focused on a fundamental architectural rewrite of our neural networks and control algorithms," Tesla said in its earnings letter.

"As we continue to collect data over time, the system will become more robust."

Tesla founder and chief executive Elon Musk has negotiated a rare contract which could net him more than $50 billion in compensation if Tesla's share price hits certain levels, but leave him dry if the company falters.

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