It would be difficult to overstate the importance of Tesla's (NASDAQ:TSLA) fourth-quarter earnings release later this month. The report follows a period of extraordinary gains for the stock. Shares have more than doubled since the beginning of October, giving the company a market capitalization of over $92 billion.

Investors will look to the electric-car marker's fourth-quarter update on Jan. 29 to see whether the company's underlying business is living up to the high expectations priced into the stock. Among other things, investors will be looking for signs of operating leverage and further growth in demand.

Here's a preview of some of the key items investors may want to check on when Tesla reports earnings.

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

Tesla vehicles. Image source: Tesla.

Automotive gross margin

Until Q3, Tesla's automotive gross margin was moving in the wrong direction, sliding from 25.8% in the third quarter of 2018 to 18.9% in the second quarter of 2019. Particularly troubling was the fact that gross margin was declining despite Tesla's improved Model 3 production volume. Investors were hoping higher production rates would lead to economies of scale and -- in turn -- a higher automotive gross margin. Fortunately, in Q3, Tesla's auto margin finally notched higher to 22.8%, giving investors more confidence in the company's ability to return to a gross margin of around 25%.

While some of this sequential improvement was due to the recognition of deferred revenue for the Smart Summon feature Tesla released to customers during the quarter, management said margin was also impacted by "fundamental improvements in our operating efficiency, including higher fixed cost absorption, reductions in manufacturing and material costs and continued improvements in vehicle quality."

Investors should look for further sequential improvement in Tesla's automotive gross profit margin since vehicle production and deliveries both hit record highs during Q4.

Shanghai factory production rate

2019 was an important year for Tesla's factory in Fremont, California. The automaker wrapped up the year with a Model 3 production run rate of about 350,000 annually -- up from a run rate of about 250,000 one year earlier.

In 2020, however, investors will have their eyes on Tesla's new factory in Shanghai. The factory, which builds Model 3 vehicles for customers in China, went online in late 2019. By Jan. 3, Tesla had made "just under 1,000 customer salable cars" and had started deliveries.

Investors should look for an update from management on Tesla's weekly production rate for vehicles in the market.

Vehicle delivery guidance

Finally, investors may want to look to Tesla's guidance for full-year vehicle deliveries in 2020. The company's outlook will likely give insight into whether demand is continuing to track upward. In addition, the forecast will provide a glimpse into management's confidence for its production and product launch plans during the year. Not only is Tesla's Model 3 production volume likely to increase throughout 2020, but the automaker plans to release a new vehicle -- Model Y -- sometime around the middle of the year.

Tesla will report its fourth-quarter results after market close on Wednesday, Jan. 29.