Several exchange-traded funds (ETFs) have gobbled up shares of Space Exploration Technologies (SPCX +1.89%) since it went public on June 12, 2026. But while major ETFs like the Vanguard Morningstar Total Stock Market ETF and the Vanguard Morningstar Growth ETF have barely increased their holdings since June, the Vanguard Communication Services ETF (VOX -1.46%) has consistently added shares every month.

In fact, SpaceX is now the seventh-largest holding in the Vanguard Communication Services ETF. As of Sept. 30, the ETF now holds 1,209,387 SpaceX shares, up from 1,170,398 shares as of Aug. 31, 842,835 shares as of July 31, and 632,077 shares as of June 30.

Here's why investors can expect the Vanguard Communication Services ETF to continue buying SpaceX shares, and why the ETF remains a top buy now.

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SpaceX's Float isn't anywhere close to 13.18 billion shares

Despite having a $1.93 trillion market cap, SpaceX is still not a top holding in many growth-focused and general market ETFs because the percentage of shares available for trading on the Nasdaq exchange (called the float) is still a relatively small percentage of SpaceX's total share count. SpaceX sold 639 million shares during its June initial public offering. It has since unlocked about 2.3 billion shares in total. But that's still just 17.5% of SpaceX's outstanding share count of 13.18 billion.

As more SpaceX shares become unlocked, SpaceX's float will increase, and so will its float-adjusted weighting in the Nasdaq-100 index, which is the 100 largest non-financial stocks by market cap in the Nasdaq Composite (^IXIC -0.21%). In turn, ETFs benchmarked to the Nasdaq-100 or that use float-adjusted weighting systems will increase their SpaceX holdings.

SpaceX is one of the three largest communication stocks

Among ETFs buying SpaceX stock, the Vanguard Communication Services ETF will likely remain one of the most aggressive, as it is a sector-based fund. Meaning that it only invests in communication stocks, which includes Alphabet (NASDAQ: GOOG) (GOOGL -1.24%) and Meta Platforms (META -0.96%) but excludes mega cap giants like Nvidia, Apple, Microsoft, and Amazon that you'd find in other growth-focused ETFs and general market ETFs.

Because Vanguard classifies SpaceX as a communications stock, the Vanguard Communication Services ETF is the only Vanguard sector ETF that will buy SpaceX. And because SpaceX's market cap is so large, it would become a top-three holding in the ETF if it were weighted by market cap rather than float-adjusted. This dynamic is why SpaceX has ascended to the seventh-largest holding in the Vanguard Communication Services ETF in a matter of months.

Alphabet and Meta Platforms are 47% of the Vanguard Communication Services ETF

The Vanguard Communication Services ETF is a great buy for investors looking to build a portfolio around Alphabet, Meta Platforms, and SpaceX. Alphabet and Meta Platforms currently make up a whopping 47% of the fund.

Adding the full weight of SpaceX's market cap to the mix will make the ETF even more top-heavy and growth-oriented. But the ETF will likely still have a reasonable valuation given that Alphabet and Meta Platforms feature forward P/E ratios of 25.9 and 23.4, respectively. What's more, the communications sector has significant weightings in value-focused industries like telecommunications and legacy media. These qualities make the Vanguard Communication Services ETF uniquely positioned to absorb the high-risk, high-reward nature of making SpaceX a top holding.