Amazon on Friday announced a sizable stake in Rivian Automotive, a start-up developing electric vehicles, including the retail giant’s commercial delivery vans.

As of Sept. 30, Amazon held equity investments “including preferred stock of Rivian Automotive, Inc. representing an approximately 20% ownership interest” that had a carrying value of $3.8 billion, up from $2.7 billion on Dec. 31, the company disclosed in an SEC filing. Amazon has invested more than $1.3 billion in Rivian to date, Rivian said in a separate securities filing earlier this month.

Rivian filed its IPO prospectus Oct. 1 and said it plans to list on the Nasdaq under the ticker symbol “RIVN.” The filing revealed new details about how closely enjoined Rivian and Amazon are. Rivian is expected to hold its IPO in November.

Rivian said Amazon has some exclusive rights to Rivian’s electric delivery vehicles for at least four years and the right of first refusal after that. Amazon has ordered 100,000 vehicles by 2030. The company plans to have 10,000 new electric delivery vehicles from Rivian on the road as early as next year.

Ford Motors also holds a stake greater than 5% in Rivian. Ford executive Alexandra English left the Rivian board in May, the company revealed in its IPO prospectus this month.

Correction: A previous headline on this story incorrectly stated the value of Amazon’s stake in Rivian. The $3.8 billion value represents all of Amazon’s equity investments not accounted for under the equity method, not just Rivian.

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