It's been a wild year for Tesla (TSLA -3.55%) shareholders. The stock is up more than 400% year to date. Over the past year, shares are up nearly 800%.

While the growth stock's big gain recently is great for shareholders, it means expectations are high going into the electric-car company's third-quarter earnings report this week. Ahead of the quarterly update on Oct. 21, here's a preview of some of the key areas investors may want to check on. 

Tesla's Model S, X, 3, and Y

Image source: Tesla.

Profitability

Sharp revenue growth for Q3 is pretty much already in the bag. A few days after the quarter ended, Tesla said it delivered record quarterly deliveries during the period, with total deliveries rising 43% year over year.

The bigger question about Tesla's financials during the quarter is regarding the company's profitability. Analyst estimates for the automaker's earnings per share for the period span a wide range, with the lowest estimate calling for $0.23 per share and the highest for $0.98. The average estimate is notably $0.56, which translates to a 51% jump compared to the year-ago quarter. 

Factory construction progress

Investors will also look to Tesla's quarterly shareholder presentation to get a progress update on the company's ongoing expansion efforts. In Q2, Tesla said it had an annual production capacity at its factory in Fremont, California of 400,000 units for Model 3 and Model Y combined. But management said that this installed capacity would extend to 500,000 units at some point in 2020. Did Tesla achieve this before Q4 started?

Further, Tesla said it was building Model Y production capacity at its factories in Shanghai and Berlin. Look to see whether the automaker completed construction on these important production lines. 

Guidance for vehicle deliveries

Finally, investors will want to see whether Tesla is maintaining its guidance for 500,000 deliveries this year. To deliver 500,000 vehicles in 2020, Tesla would need to deliver more than 181,000 vehicles in Q4 alone. This would imply huge growth both year over year and sequentially, as Tesla delivered about 112,000 and 139,000 vehicles in the fourth quarter of 2019 and the third quarter of 2020, respectively.

Regarding vehicle delivery guidance, investors should also look to see if Tesla provides any commentary on demand for its vehicles. Did Tesla exit Q3 with a record backlog of vehicle orders? Without record orders, Tesla may not maintain full confidence from investors in the company's growth story.

Tesla reports its third-quarter results after market close on Wednesday.