LOSANGELES— Adding acompanytothebenchmark S&P 500 stock index is typically a mundane exercise — except when it comes to a company like Tesla.

The market value of the electric car maker, led by Elon Musk, has soared to around$600billion, making it the largest company ever to be added to the S&P 500.

It’s inclusion Monday is expected to trigger a torrent of trading by institutional investorsandaspikeinvolatility.

Index funds designed to mirror the holdings of the S&P500,whichisattheheart ofmany401(k) accounts, are expected to snap up more than $80 billion worth of Tesla’ssharesbeforethestart of trading Monday as funds move to rebalance their holdings for the quarter.

That’s projected to push the amount spent on tradingtorebalanceportfoliosin thefourthquartertoarecord high, said Howard Silverblatt, senior index analyst at S&P Dow Jones Indices.

“Historically, the $21 billion trading for fourth-quarter rebalancing is minor league, but when you add in heavy-hitter Tesla, $82billion, youendup doubling the historical high, surpassing the $100 billion mark,” he said.

Because the S&P 500 is weighted by market capitalization, Tesla will be one of the10mostvaluablecompanies in the index, along with Apple, Microsoft, Amazon, FacebookandGoogleparent Alphabet. That increases the likelihood that a few big stocks will heavily influence the index’s performance, something that’s been happening in recent years.

Tesla’s sky high valuation means a move in its stock price will have more of an impact on the S&P 500 than most companies. The median weighting of the index is 0.08%, while Tesla’s weighting is projected to be around 1.5% to 1.6%. Apple has the largest weighting at 6.5%.

“So, the weighting itself is not as large as the Big Tech firms that tend to move the market,” said Pauline Bell, equity research analyst at CFRA Research. “On the other hand, it’s not a small fish. It’s still a large chunk of the S&P 500 index.”

Teslabecameeligibletobe includedintheS&P500after posting its fourth consecutive profit in the second quarter of this year.

The company’s shares have soared 650% this year as investors cheered the fact that the automaker is finally making money after years of losses and continues to hit milestones for deliveries of its vehicles.

“Ifyoulookattodayversus a couple of years ago, it’s a company that has demonstrated staying power and some competitive advantages,” said Tom Martin, senior portfolio manager with Globalt Investments.

“What it’s worth is a different question.”

The stunning run-up in Tesla shares has sometimes been attributed less to its ability to deliver profits than to enthusiasm by investors, particularly newcomers day-trading on platforms likeRobinhood, whereTesla is among the 100 most-held stocks by its users.

That’s led to periods of volatiletradingforthestock, whichstarted2020at$88.60 pershare.andhitanall-time high of $649.88 this month.