Rivian Automotive, a start-up building electric cars, is trying to steal some market share from Tesla with the recent 20% stake acquisition by Amazon.

The company disclosed in an SEC filing that it held equity investments valued at $3.8 billion at the end of September, up from $2.7 billion at the end of December 2020, including preferred stock in Rivian Automotive, Inc., representing approximately 20% ownership interest.

Rivian said in a separate security filing earlier this month that Amazon has invested more than $1.3 billion in the company.

The SEC filing revealed that Rivian and Amazon are closely aligned in its IPO prospectus filed October 1. In the filing, Rivian said it plans to list on the Nasdaq under the ticker symbol “RIVN.” The offering is expected to take place in November.

Rivian said Amazon had the right of the first refusal beyond four years for Rivian’s electric delivery vehicles. By 2030, Amazon plans to purchase 100,000 electric vehicles. Within the next year, Rivian expects to put 10,000 electric delivery vehicles on the road.

Ford Motors also owns a stake of more than 5% in Rivian. Rivian revealed in its IPO prospectus this month that Ford executive, Alexandra English left the board in May.

This is the largest expansion Rivian has undertaken at the Normal property since it acquired it in 2017.

A 623,000-square-foot addition to Rivian’s site plan is proposed for the plant’s west side, bringing its total size to about 3.9 million square feet.

In order to continue vertical integration, Rivian needs more production space inside the facility. According to the spokesman, Zach Dietmeier, the expansion is part of a plan to invest in the facility and ramp up production in Normal.