SpaceX vaults to No. 1 in $97.7 billion Vanguard ETF on float quirk

SpaceX's tiny 5 percent public float has vaulted the $1.6 trillion company to the top of the $97.7 billion Vanguard Extended Market ETF, a fund designed for small- and mid-cap stocks.

"The S&P Completion Index weights constituents by float-adjusted market cap, not total market cap, so SpaceX's limited float classified it alongside mid-caps," said Daniel Foelber, a markets contributor at The Motley Fool. "That anomaly will correct as shares unlock."

The Vanguard Extended Market ETF held 6.8 million SpaceX shares worth $1.16 billion as of June 30, making it the No. 1 position among 3,372 stocks. Across nine Vanguard ETFs, the firm holds about $6.1 billion in SpaceX stock, with the Vanguard Total Stock Market ETF alone owning 18.7 million shares valued at $3.2 billion.

As SpaceX unlocks 20 percent of Early Release Eligible Shares on Aug. 6 and up to 55 percent by October, its ETF weightings will shift dramatically. The Extended Market ETF will likely shed its SpaceX position entirely, while growth and total market funds will increase allocations toward levels comparable to Meta Platforms.

SpaceX went public on June 12 in the largest IPO in history, selling 555 million shares at $135 each to raise $75 billion. With only about 5 percent of total shares available for trading, the company's float-adjusted market capitalization is far below its $1.63 trillion total valuation. That discrepancy has created unusual index classification dynamics.

The S&P 500 Completion Index, which the Vanguard Extended Market ETF tracks, weights constituents by float-adjusted market cap. Because SpaceX's public float is so small, the index classified it alongside mid-cap and small-cap stocks, propelling it to the fund's top holding in less than three weeks. The same dynamic explains why SpaceX represents just 0.29 percent of the Vanguard Growth ETF, compared with Meta Platforms' 3.4 percent weighting despite similar total market caps.

Float unlocks will reshape ETF exposure

The Aug. 6 unlock of 20 percent of Early Release Eligible Shares marks the first of several events that will normalize SpaceX's ETF weightings. As the float expands, index providers will recalculate the company's float-adjusted market cap, triggering rebalancing across funds.

For the Vanguard Extended Market ETF, this likely means a complete exit from SpaceX before year-end, Foelber said. The fund's $1.16 billion position would be redistributed to other mid-cap holdings. Conversely, the Vanguard Growth ETF, Vanguard Mega Cap Growth ETF, and Vanguard Total Stock Market ETF are expected to increase their SpaceX allocations toward market-cap-weighted levels.

The Vanguard Total Stock Market ETF, with its 0.03 percent expense ratio and $3.2 billion SpaceX position, offers the broadest exposure. The fund added SpaceX faster than S&P 500-tracking ETFs, which must wait at least a year after the IPO for inclusion. It will likely add upcoming megacap IPOs from Anthropic and OpenAI on a similar timeline.

SpaceX's inclusion in the Nasdaq-100 on July 7, just 25 days after its IPO, shows how index providers are adapting to megacap listings. The company's market cap of roughly $1.5 trillion places it alongside Meta Platforms as one of the 10 largest U.S. companies — a size that makes its temporary classification as a mid-cap holding an anomaly that will resolve as lockup periods expire.

This article is for informational purposes only and does not constitute investment advice.