As of the end of March, the company said its investment was worth $2.48 billion, based on the surge in bitcoin in the first quarter.

On the company's statement of operations, that gain shows up as a reduction in operating expenses, suggesting that it flipped some of its holdings as bitcoin prices rose that quarter.

But the price of bitcoin plunged more than 40% in the second quarter, so Tesla's holdings would be worth much less than at the end of the first quarter. The cryptocurrency peaked above $63,000 in April, and then dropped below $30,000 earlier this month.

In those instances, companies typically mark their holdings every quarter based on the market price, determining the value by a follow-on financing round or a public stock price.