Kurt Schlosser, GeekWire

As it waits on its order of tens of thousands of delivery vans, Amazon revealed Friday that it has a 20% stake in Rivian, the electric vehicle maker that it's been heavily investing in since 2019.

In a new SEC filing, the tech giant disclosed an equity interest in the startup, which is part of its overall equity investments carrying value of $3.8 billion, up from $2.7 billion at the end of 2020.

As of December 31, 2020 and September 30, 2021, equity investments not accounted for under the equity-method and without readily determinable fair values, including preferred stock of Rivian Automotive, Inc. representing an approximately 20% ownership interest, had a carrying value of $2.7 billion and $3.8 billion, and are recorded within "Other assets" on our consolidated balance sheets with adjustments recognized in "Other income (expense), net" on our consolidated statements of operations.

Amazon has backed Rivian through its Climate Pledge Fund, which is aimed at investing in companies that accelerate Amazon's pledge to be net zero carbon across its businesses by 2040. Amazon was among lead investors in a $2.5 billion financing round in Rivian in July and previously backed Rivian in 2019 in rounds of $700 million and $1.3 billion.

Founded in 2009, Rivian has raised about $10.5 billion to date. It announced plans this summer to go public at a reported valuation of $80 billion.

Amazon ordered 100,000 electric delivery vans through Rivian and said last October that it hoped to have 10,000 of them on the road as early as 2022.

The EV maker has begun production and delivery of its R1T all-electric pickup truck and will launch the R1S sport utility vehicle in December.

This story first appeared on GeekWire.