The Nasdaq-100 has been far more volatile than the S&P 500. Now add SpaceX to the mix.

By Christine Idzelis

While SpaceX is due to join the Nasdaq-100 on Tuesday, it isn't eligible to become part of the S&P 500 for at least another year - likely furthering the volatility spread between those two indexes

SpaceX will become part of the Nasdaq-100 index before the market opens on Tuesday.

The Nasdaq-100 has already been unusually volatile relative to the S&P 500 - and now it's about to gain exposure to a stock known for making dramatic moves.

The Cboe Nasdaq-100 Volatility Index XX:VXN, which trades under the ticker symbol "VXN," has surged around 43% this year through Thursday, as U.S. investors headed into the three-day holiday weekend, according to FactSet data. That's a far bigger jump than the 8% one seen for the Cboe Volatility Index VIX, a measure of options activity linked to the S&P 500, which indicates volatility expected over the next month.

Enter SpaceX (SPCX), which is due for fast-track inclusion into the Nasdaq-100 on Tuesday. While the Nasdaq relaxed its rules for index entry, paving the way for SpaceX to join quickly after making its trading debut on June 12, S&P Dow Jones Indices declined to change the rules for SpaceX and other large companies. That means SpaceX will have to wait at least a year to join the S&P 500 based on current rules - and maybe longer, given the index's profitability requirements.

SpaceX has been a volatile stock in its short time on the public market, and its imminent inclusion in the Nasdaq-100 - but not the S&P 500 - could keep the volatility spread between those two indexes wide, an equity derivatives strategist at RBC Capital Markets said in a note emailed Sunday.

RBC Capital Markets

Despite the volatility for SpaceX shares, they still trade above their initial-public-offering price of $135 per share and their opening price of $150.

"IPOs are inherently volatile, and especially in those early weeks" after a company goes public, said Avery Marquez, director of investment strategies at Renaissance Capital, in a phone interview Monday. Shares of companies that only recently have gone public tend to be more vulnerable when market sentiment broadly turns sour, as investors may not feel comfortable holding a stock that lacks a long trading history or a track record of profitability as a public company, she said.

SpaceX's upcoming inclusion in the Nasdaq-100 means its publicly traded shares will soon be held by the giant Invesco QQQ Trust Series I ETF QQQ, which tracks the index. The company previously secured inclusion in the Russell 1000 Index, a much broader index of U.S. large-cap and mid-cap stocks.

As recently as July 2, SpaceX had a tiny weighting of 0.1% in the iShares Russell 1000 ETF IWB, according to data on BlackRock's website.

Although SpaceX has a massive market value, only about 5% of its shares are publicly floated, Marquez said, which means the company could also have a relatively small weighting in a benchmark such as the IPO index tracked by the Renaissance IPO ETF IPO.

That ETF, which provides exposure to the largest recently listed stocks in the U.S., could hold SpaceX later this year. Those behind the index it tracks will evaluate whether to include it at the time of the next quarterly rebalancing, said Marquez.

The fund's portfolio doesn't currently share any constituents with the S&P 500 and just three of the stocks in the IPO index it tracks are also in the Nasdaq-100, including Astera Labs (ALAB), the U.S. listed shares of Arm Holdings (ARM) and CoreWeave (CRWV), according to Marquez.

Shares of the Renaissance IPO ETF have surged 28.4% this year through Monday, easily beating the S&P 500's gain of 10.1% and the Invesco QQQ Trust Series I ETF's 17.7% surge, according to FactSet data.

The QQQ ETF's largest holdings as of July 2 were Nvidia (NVDA), Apple (AAPL), Micron Technology (MU), Microsoft (MSFT) and Amazon (AMZN), according to data on Invesco's website. Four of those stocks are within the Big Tech cohort known as the "Magnificent Seven," except for Micron - whose stock has skyrocketed this year after benefiting from huge demand for memory chips in the race to build out artificial intelligence.

The top five holdings of the Renaissance IPO ETF on Monday were Astera, Arm, CoreWeave, Reddit (RDDT)and Medline (MDLN), according to data on the website of Renaissance Capital, which also is a provider of pre-IPO research.

Meanwhile, SpaceX shares finished 1% lower on Monday, even as major U.S. stock benchmarks rose. The company has a market value of more than $2 trillion, but with only about 5% of its shares being publicly floated, heavy interest in buying and selling SpaceX can create more volatile shifts in its stock price.

Louis Navellier, chief investment officer at Navellier & Associates, told MarketWatch in an interview on Monday that he'd consider buying shares of SpaceX after the company's "insiders" have unloaded some of their own shares and once it appears that the company will have a profitable quarter.

The U.S. stock market closed higher Monday, with the S&P 500 SPX, Nasdaq Composite Index COMP and Dow Jones Industrial Average DJIA all posting gains. The Invesco QQQ Trust Series I, which has around $489 billion of assets under management, outperformed all three major benchmarks, with a sharp 1.4% gain, FactSet data showed.

William Gavin contributed.

-Christine Idzelis

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