By Mark McSherry

Shares of Tesla fell 21% on Tuesday, wiping about $82 billion from its stock market valuation, after the electric vehicle maker’s surprise exclusion from the S&P 500 deprived it of automatic demand from passive funds.

Baird analyst Ben Kallo wrote: “We think shares were reflecting expectations for substantial passive inflows …”

There are an estimated $4.5 trillion of assets indexed to the S&P 500.

“We think the stock could be under pressure following the delay of S&P 500 inclusion, particularly from investors who bought ahead of the announcement expecting an opportunity to sell to passive funds,” added Kallo.

Tesla shares fell to to $330.21 to give the firm a current stock market value of around $308 billion, according to Bloomberg data. The stock was trading around $498 last week.

Edinburgh investment giant Baillie Gifford is one of Tesla’s largest outside shareholders.

Baillie Gifford said last week it had been forced to trim its position in the electric vehicle maker because Tesla’s spectacular share price rise in the past 12 months has made the stock too big an influence on the fund company’s holdings.

It is estimated the move generated profits of about $17 billion for Baillie Gifford funds. 

Baillie Gifford fund manager James Anderson said last week the firm intended to remain a significant shareholder in Tesla for “many years” and that “should there be serious setbacks in the share price we would welcome the opportunity to once again increase our shareholding.” 

A recent filing with the US Securities and Exchange Commission showed that Baillie Gifford now owns under 5% of Tesla, down from around 6.3%. 

At one stage, the Edinburgh fund manager owned 7.7% of Tesla.

Tesla also said Tuesday it completed a sale of $5 billion of new shares last Friday.