After Tesla reported $139 million profit for the fourth quarter of 2018, generating a record $7.2 billion in revenue, its Founder and CEO Elon Musk dropped a bomb, saying the company's Indian-origin Chief Financial Officer Deepak Ahuja will be retiring.

In an earnings call with analysts late Wednesday, Musk said that Ahuja's retirement "won't be immediate" and that "he will continue to serve as a senior adviser to the company".

Following the announcement, Tesla stocks fell about 5 per cent in after-hours trading.

Zach Kirkhorn, the company's current Vice President of Finance, will replace Ahuja.

"There is no good time to make this change. It's a new chapter, a new year. Tesla has had two great quarters of profitability and cash flow, it's on a really solid foundation," Ahuja told analysts.

Ahuja, who worked out of Tesla's San Carlos headquarters, quit Tesla in 2015, only to rejoin in 2017.

Tesla's Chief Accounting Officer has also left the company after less than a month.

Earlier in the day, riding on the success of its Model 3 car, Tesla reported revenue for the full year at $21.4 billion -- another record for the electric car maker.

With nearly 140,000 units sold, Model 3 was also the best-selling premium vehicle (including SUVs) in the US for 2018 -- the first time in decades an American carmaker has been able to secure the top spot.

"In 2019, full-year Model 3 volumes will grow substantially over 2018 due to a full year of high production rates at our Fremont facility," said Tesla in a statement.

"In Q4, we delivered 63,359 Model 3 vehicles to customers in North America. In January 2019, we started to produce Model 3 vehicles for Europe and China, and the car is now fully certified for sale in these markets," the company added.

In January, Tesla started construction of Gigafactory Shanghai.

"Local manufacturing is an essential component of our ability to provide to customers in the region a truly affordable version of Model 3," said Tesla.