What happened

Rivian Automotive (RIVN 2.44%) stock was trading down 2% as of 12:45 p.m. ET today. An update from e-commerce giant Amazon sent shares of Rivian rallying 2.9% higher in early morning trading, but the electric vehicle (EV) stock failed to sustain momentum. Investors, perhaps, are nervous ahead of Rivian's upcoming earnings release.

So what

This morning, Amazon revealed its EV fleet now has more than 1,000 delivery vans, all from Rivian, and that they'll be used to deliver packages in over 100 cities in the U.S. in the upcoming holiday season. It will be the first such holiday season when Amazon will use electric vehicles for deliveries.

Amazon further stated that it's working with Rivian to roll out "thousands" of electric delivery vans (EDVs) by the end of 2022 and 100,000 EDVs by 2030.

To be fair, there's nothing new in this update except for the fact that investors in Rivian now have an idea about how many EDVs the company has delivered to Amazon so far. The e-commerce company placed an order for 100,000 EDVs in 2019, and this deal was one of the biggest factors behind Rivian stock's blockbuster debut in the U.S. during its initial public offering in November 2021.

Now what

Rivian will release its third-quarter numbers on Nov. 9, but there may not be many surprises in store for investors. Rivian has already announced that it produced 7,363 EVs and delivered 6,584 units in the quarter that ended Sept. 30. That represents almost 47% growth in deliveries sequentially. As for production, Rivian states that it's on track to produce 25,000 units in the full year as previously guided.

Investors, though, should look beyond 2022, and one number they'd want to watch out for on Nov. 9 is Rivian's backlog and how fast it is growing. As of June 30, the company had roughly 98,000 net preorders for its R1T pickup trucks and said its average daily preorder rate in Q2 was higher than in the first quarter.