US electric carmaker Tesla held almost $2 billion worth of Bitcoin by the end of last year, according to financial filings to the Securities and Exchange Commission (SEC) on Monday.

"In the first quarter of 2021, we invested an aggregate $1.5 billion in Bitcoin. We believe in the long-term potential of digital assets both as an investment and also as a liquid alternative to cash," the filing said.

"The fair market value of our Bitcoin holdings as of December 31, 2021 was $1.99 billion," it added.

Tesla CEO Elon Musk said early last year that the company started to accept Bitcoin as a mode of payment, but the firm stopped this option in May amid environmental concerns.

Bitcoin, the world's largest cryptocurrency by market capitalization, ended 2021 with a gain of approximately 60%, trading just above $46,000 on Dec. 31.

Although price of Bitcoin fell below $30,000 last July 20, it climbed to an all-time high level of $69,000 on Nov. 10.

Despite its sharp decline since then due to high volatility, Bitcoin recovered in recent days and climbed above $44,000 at 11.35 a.m. EDT.

Tesla is the world's second-largest publicly traded company, after MicroStrategy, which owns Bitcoin. The company is estimated to hold almost 43,000 Bitcoin./aa