If you traded stock in the past week, there's a fair chance it was Tesla.

Shares in the electric car maker led by CEO Elon Musk rose almost 3% on Wednesday and have now surged 40% since Nov. 16, when it was announced Tesla would join the S&P 500 in December. Investors rushed to buy shares ahead of index funds that will be forced to acquire over $50 billion of its shares.

One of Wall Street's most loved – and hated – stocks, Tesla was already the U.S. stock market's most traded companies by average daily value, but trading has surged in recent sessions, along with Tesla's stock price.

"It's been crazy. Since Tesla's (announced) inclusion in the S&P, you've had a lot of managers out there that didn't own enough of it having to buy more," said Sahak Manuelian, managing director of trading at Wedbush Securities, in Los Angeles.

Retail investors using apps like Robinhood are also responsible for much of the recent volume spike, Manuelian added.

Traders bought and sold an average of nearly $26 billion of Tesla shares per session over the five days ending on Tuesday, accounting for almost 8% of all stock traded on U.S. exchanges, according to Refinitiv data. That is more than the combined value of trades in Amazon.com Inc and Apple Inc over the same period.

At about halfway through Wednesday's session, traders had exchanged $20 billion worth of Tesla shares, according to Refinitiv.

Up over 400% in 2020, Tesla has become by far the world's most valuable automaker, despite production that is a fraction of Toyota Motor Corp, Volkswagen or General Motors Co.

Over the past year, Tesla has averaged over $16 billion a day in trades, followed by Apple, at about $14 billion, according to Refinitiv data.

Trading in Chinese electric vehicle maker NIO Inc has also surged in recent weeks, with its shares nearly doubling in November.

Including NIO, trading of stocks in the nascent electric vehicle industry reached an average of $38 billion a day in the past five sessions, accounting for 12% of all trading on U.S. exchanges. By comparison, traders in the same period bought and sold each day about $8 billion worth of oil and gas stocks including Exxon Mobil and Chevron.