SpaceX Just Went Public — Here is How It Could End Up In Your 401(k)

SpaceX, Elon Musk's space-and-AI conglomerate, went public last week in a record-breaking IPO valued at $2 trillion — making it one of the largest publicly traded companies in the world overnight. But even if you didn't buy shares on day one, you might end up owning SpaceX anyway. It could show up in your 401(k), your index fund, and your retirement account whether you like it or not.

## The Index Inclusion Race Has Already Started

Here's how this works: many funds held in 401(k)s track benchmark stock indexes. When a company gets added to an index, the funds tracking that index automatically buy its shares. SpaceX is now eligible for several major indexes, and the race to include it has already begun.

**Nasdaq moved fast.** In May, the Nasdaq adjusted its rules to allow faster inclusion of mega IPOs like SpaceX into the Nasdaq 100, shortening the waiting period from three months to just 15 days. That means SpaceX could join the Nasdaq 100 — and by extension, the funds that track it — within weeks.

**FTSE Russell also adjusted its rules** for quicker inclusion, and CRSP, another benchmark provider, could add SpaceX after just five trading days.

**The S&P 500 is the holdout.** S&P Dow Jones Indices said on June 4 it won't fast-track SpaceX into the S&P 500, meaning the most widely tracked U.S. index won't include it for at least a year. For reference, Tesla went public in 2010 and didn't join the S&P 500 until 2020.

## But Don't Expect a Huge Impact Right Away

Even though SpaceX's $2 trillion valuation puts it in the top 10 largest U.S. public companies, its actual weight in indexes will start small. The company went public with less than 5% of its shares available for trading, meaning its index weight will be a fraction of what its valuation suggests.

"The stock's performance shouldn't meaningfully affect the direction of major indices that hold it," said Mike Dickson, head of research and quantitative strategies at Horizon Investments.

Rodney Comegys, CIO at Vanguard Capital Management, echoed that: "No matter which index we're talking about, the mega IPOs will enter the benchmarks as relatively modest weights."

This is important for everyday investors to understand. If you own a total market index fund, SpaceX will be in there — but at a tiny weighting initially. Your exposure won't be dramatic unless you're actively buying SpaceX shares.

## Why This Matters Beyond Musk

SpaceX's IPO is significant not just because of its size, but because it represents a new category of public company: a vertically integrated space-and-AI conglomerate that generates revenue from satellite internet (Starlink), government contracts (NASA, Department of Defense), and emerging ventures like point-to-point Earth transport and Mars colonization infrastructure.

The company's inclusion in index funds means that millions of retirement savers will now have indirect exposure to the commercial space industry — an industry that didn't exist as a public investment category a decade ago. It also means that SpaceX's volatility will ripple through retirement portfolios in ways that most participants won't notice until there's a significant move.

## What This Means For You

**If you have a 401(k) or IRA invested in index funds, you will likely own SpaceX soon** — whether you chose to or not. Here's what to think about:

- **Check your target-date and total market funds.** These are the most likely vehicles for early SpaceX exposure. If you own a Nasdaq 100 fund, it could happen within weeks.

- **Understand the float problem.** With less than 5% of shares publicly available, SpaceX stock will be volatile. Small supply + enormous demand = big price swings. This volatility will bleed into any fund that holds it.

- **Don't confuse index inclusion with a recommendation.** Index funds buy companies based on size and eligibility, not because they're good investments. SpaceX may be revolutionary, but it's also unprofitable on a GAAP basis and operates in an industry with no established playbook.

- **If you want to avoid SpaceX specifically**, you'll need to look at which funds hold it and consider alternatives. But for most investors in broad index funds, the exposure will be small enough that it shouldn't drive portfolio decisions.

- **If you want more SpaceX exposure**, understand that you're betting on a company that combines the regulatory risk of a defense contractor, the capital intensity of an infrastructure company, and the valuation expectations of a tech growth stock. It could be extraordinary — or it could be a long, expensive wait for profitability.

The bottom line: SpaceX's public debut marks a structural shift in what "the market" means. When a $2 trillion space company enters your retirement account by default, the definition of a diversified portfolio has officially expanded beyond Earth.