Space stocks index builder to set your own SpaceX weight and backtest it against every space ETF
The new space funds put a fifth to two fifths of your money in one stock. One older fund holds none. Pick the space companies you want, choose the SpaceX share yourself, and see how the basket would have done next to the S&P 500 and the funds. Then buy it at your own broker.
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Educational only · Never places a trade
In short
A space stocks index is a weighted basket of the listed companies whose main business is space: launch, satellite connectivity, Earth imaging and spacecraft. Since SpaceX listed on Nasdaq in June 2026, the space ETFs differ mostly in how much of it they hold. On their late September 2026 holdings files, Roundhill's MARS held 24.4% in SpaceX, Tema's NASA 24.2%, Global X's ORBX 22.7% and VanEck's WARP 20.2%, while State Street's ROKT held none. Building your own space stocks index means choosing that SpaceX weight and every other weight yourself, backtesting the basket, and buying the stocks at a broker with no expense ratio.
Summed from each fund's published holdings
How much SpaceX is in each space ETF, and how much of the rest is space?
The dark part of each bar is SpaceX. The red part is every other company whose main business is space. The pale rest is something else: defense contractors, GPS makers, chip companies or ocean equipment.
Baron RONB
40.3% of 40.3%
Sep 29. A growth fund, the only space company it holds is SpaceX
Roundhill MARS
24.4% of 99.6%
Sep 30 close
Tema NASA
24.2% of 76.3%
Sep 30. 16.7% through a SpaceX private vehicle, 7.5% in listed shares
Global X ORBX
22.7% of 99%
Sep 30
VanEck WARP
20.2% of 97.7%
Sep 29. Its index caps any one stock at 20%
ARK ARKX
10.8% of 19.1%
Oct 1. Most of the rest is defense, drones and chips
Procure UFO
3.8% of 55.4%
Jul 31 SEC filing, the latest the issuer has filed
SPDR ROKT
0% of 22.4%
Sep 29. Does not hold SpaceX
Read the bars in pairs. The four funds launched in 2026 (MARS, NASA, ORBX and WARP) are three quarters or more space companies, and about a fifth to a quarter of each is SpaceX. That is not an accident of stock picking. SpaceX was worth roughly $2 trillion at its September 30 price of $150.86, far more than every other listed space company put together, so a space index weighted by market value would be little else. WARP's index caps any one stock at 20%, which is why SpaceX sits right at that line.
The two older index funds went the other way, for different reasons. ROKT's index counts deep sea exploration and aerospace suppliers alongside space, and it held no SpaceX at all. UFO counts companies by where their revenue comes from, which brings in Garmin, Trimble and Sirius XM; its last SEC filing, for July 31, showed SpaceX at 3.8%, and press coverage since then reports the weight has risen, so check the fund's current file. ARKX is an active fund that mixes space with defense, drones and chips. And RONB is not a space fund at all: it is a growth fund that happens to hold 40% of itself in one rocket company.
None of these is wrong. They are eight different answers to the question of how much of a space portfolio should ride on one stock, and the funds answer it for you. A basket of your own lets you answer it yourself, whether that is 0%, 10% or 30%.
From each issuer's fund page, holdings file and SEC filings
Which space ETF holds what, and how does each one choose its stocks?
| Fund | Expense ratio | Stocks | Rule | Largest positions |
|---|---|---|---|---|
| Procure Space (UFO) | 0.75% | 64 | S-Network Space Index, companies earning most of their revenue from space | Garmin 7.0%, Trimble 6.3%, Viasat 6.2%, Sirius XM 5.8%, EchoStar 4.2% (Jul 31 filing) |
| ARK Space & Defense Innovation (ARKX) | 0.75% | 33 | Actively managed, space plus defense, drones and AI | SpaceX 10.8%, L3Harris 6.2%, Rocket Lab 5.9%, Deere 5.6%, Kratos 5.5% (Oct 1) |
| SPDR S&P Kensho Final Frontiers (ROKT) | 0.45% | 34 | S&P Kensho index of space and deep sea exploration companies | Forum Energy 4.4%, Oceaneering 3.9%, Ducommun 3.9%, RTX 3.7%, Iridium 3.7% (Sep 29) |
| Roundhill Space & Technology (MARS) | 0.75% | 28 | Actively managed, launched March 2026 | SpaceX 24.4%, Rocket Lab 10.1%, AST SpaceMobile 7.0%, Globalstar 5.1%, Viasat 4.7% (Sep 30) |
| Tema Space Innovators (NASA) | 0.75% | 36 | Actively managed, launched March 2026, part of its SpaceX held through a private vehicle | SpaceX 24.2%, Rocket Lab 10.4%, AST SpaceMobile 6.9%, Viasat 5.2%, Universal Microwave 4.9% (Sep 30) |
| VanEck Space (WARP) | 0.50% | 20 | MarketVector Space Index, 20% cap on any one stock, launched May 2026 | SpaceX 20.2%, Rocket Lab 14.5%, AST SpaceMobile 6.5%, EchoStar 4.9%, Viasat 4.8% (Sep 29) |
| Global X Space Tech (ORBX) | 0.50% | 36 | Global X Space Tech Index, launched April 2026 | SpaceX 22.7%, Rocket Lab 10.4%, AST SpaceMobile 9.6%, Iridium 4.6%, Globalstar 4.6% (Sep 30) |
| Baron First Principles (RONB) | 1.00% | 21 | Actively managed growth fund, not a space fund, listed here for its SpaceX weight | SpaceX 40.3%, Tesla 8.6%, FIGS 4.6%, MSCI 4.3%, Shopify 4.1% (Sep 29) |
Size and age vary as much as the holdings. Tema's NASA reached $1.14 billion within six months of its March 2026 launch, ARKX holds roughly $740 million and UFO $587 million at its July filing. ROKT had $173 million. MARS, ORBX and WARP each held $41 million to $46 million at the end of September, small enough that the gap between the bid and the ask can cost more than a year of fees on a quick round trip, so check the spread before you buy.
Two details sit behind the SpaceX numbers. NASA holds 16.7% of its SpaceX through what its file labels a SpaceX SPV, a private vehicle it bought into before the listing, and 7.5% in listed shares. And the expense ratios cluster tightly: 0.45% to 0.50% for the index funds ROKT, WARP and ORBX, 0.75% for the active funds and UFO, 1.00% for RONB. On $25,000 that is $113 to $250 a year. The full fee ranking, and the funds that hold the least SpaceX, are in our guide to the space ETF without SpaceX.
// The universe, four orbits
Which stocks belong in a space stocks index?
Twenty-three companies listed on Nasdaq or the NYSE earn most of their money from space. They sell four different things, and the mix you choose between them decides what your index really bets on.
1
Launch
2
Connectivity from orbit
3
Earth data and imaging
4
Spacecraft, stations and the Moon
Launch is where SpaceX and Rocket Lab sit, and it is where most of the theme's value is concentrated. Outside SpaceX, connectivity is where most of the established revenue sits: Viasat, EchoStar and Iridium sell broadband and phone service that already pays the bills, while AST SpaceMobile is building a network to reach ordinary phones from orbit. Earth data companies sell imagery and signals to governments and businesses. The outer ring builds the hardware, from satellite buses to lunar landers, and holds the smallest companies.
Most of these companies are young and several report losses, so this is a list of what is listed, not a recommendation. A useful way to build the index is to decide the share for each ring first, then the stocks inside it. Weighting is the second decision: by market value SpaceX swallows the index, so most people cap it or use an equal weight index for the rest.
From a view on space to a basket you can buy
How to build your own space stocks index in four steps
1
Pick the SpaceX weight
Decide first how much rides on SpaceX: none, a 10% sleeve, or the 20% the index funds use. Everything else follows from that number.
2
Fill the four rings
Search the catalog of US-listed stocks and ETFs, add 10 to 20 space names across launch, connectivity, data and hardware, and set equal, market value or your own weights.
3
Backtest against the funds
Run it against the S&P 500 and the Nasdaq-100, and build a one-line index of UFO or ARKX to put a fund with a long history on the same chart.
4
Track it, then buy it
Follow the index daily against its benchmark, export the weights, and place the basket at your own broker when you are ready.
Be careful with the backtest, because this theme has very short histories. SpaceX has traded only since June 12, 2026, and the four new funds since March to May 2026, so any basket that holds SpaceX can be tested only from that date. Test the rest of the basket on its own over a longer window, through the 2021 to 2022 fall in space stocks, and look at the maximum drawdown beside the S&P 500 before you look at the return. Backtests are hypothetical and past returns do not predict future ones. Because these stocks move fast, also test a quarterly reset with the custom index rebalancing tool, which is what keeps a SpaceX cap a cap.
Three ways to own the space economy, compared honestly
Build your own space index vs a space ETF vs a basket broker
| Space ETF | Fidelity Basket Portfolios | Indexes, then your broker | |
|---|---|---|---|
| Who sets the SpaceX weight | The fund, from 0% to 40% | You | You, and you can test it first |
| Yearly cost | 0.45% to 1.00% of the balance | $4.99 a month flat | From $24 a month for the software, plus your broker's cost |
| History you can test | Since 2018 to 2021 for the older three, months for the rest | None | As far back as your youngest stock goes |
| Private holdings | NASA holds part of its SpaceX through a private vehicle | None, listed shares only | None, listed shares only |
| Per-stock tax losses | No | Yes, done by you | Yes, at your broker |
| Where it falls short | You take the fund's answer on SpaceX | No way to test a design before buying | You place and rebalance the trades |
The ETF wins when you want one ticker and no upkeep, and when a fund's SpaceX weight already matches your view. WARP and ORBX at 0.50% are reasonable, low cost ways to hold the pure plays with SpaceX at about a fifth. Building your own wins once the balance is large enough that a flat $59.88 a year beats the fund fee, about $8,000 against a 0.75% fund and $12,000 against a 0.50% fund, and whenever the SpaceX weight you want is one no fund offers.
Owning the shares has a tax side that matters in a theme this volatile. In most years some space stocks fall while others rise, and each one carries its own cost basis, so a loser can be sold for a tax loss while the rest of the basket stays in place. A fund only lets you sell the whole thing. Check the dates with the wash sale calculator before you buy the same name back.
What Indexes does and does not do: it is index construction, backtesting and tracking software. It does not hold money, place trades or give investment advice. You design and test the space stocks index here and hold it wherever you already invest.
Space ETF and SpaceX questions
What people ask before they buy space stocks
Which ETF has the most SpaceX?
Of the US-listed funds, the Baron First Principles ETF (RONB, 1.00%) held the most, 40.3% on September 29, 2026, but it is a growth fund rather than a space fund. Among dedicated space ETFs, Roundhill's MARS held 24.4%, Tema's NASA 24.2%, Global X's ORBX 22.7% and VanEck's WARP 20.2%. ARK's ARKX held 10.8% on October 1.
What is the best space ETF?
It depends on what you want the fund to be. WARP and ORBX (both 0.50%) are the cheapest funds that hold almost nothing but space companies, each with about a fifth in SpaceX. ROKT (0.45%) is cheaper still but holds no SpaceX and is mostly aerospace, defense and ocean equipment. MARS and NASA (0.75%) are actively managed with similar SpaceX weights.
Is there an ETF for SpaceX alone?
Only leveraged ones. Since the June 2026 listing, several issuers launched funds that aim for twice the daily move of SpaceX shares, and Kurv launched an option income fund on the stock. They reset daily and are built for short trades. To hold SpaceX alone without leverage, you buy the SPCX shares themselves at a broker.
Does VOO hold SpaceX?
No. Vanguard's S&P 500 ETF (VOO) held no SpaceX on August 31, 2026, because S&P Dow Jones Indices kept its 12 month seasoning rule for new listings in the S&P 500. Vanguard's total market fund (VTI) held 0.11% and its extended market fund (VXF) 1.01%, because their indexes gained a fast entry route for large IPOs in June 2026.
Does Vanguard have a space ETF?
No. Vanguard has no space or aerospace theme fund. The Vanguard fund with the most SpaceX by weight is the extended market ETF (VXF, 0.05%), at 1.01% on August 31, 2026. Owning the space theme through Vanguard means a broad fund with a sliver of space, or a basket of the space stocks bought in a Vanguard brokerage account.
Is SpaceX in the S&P 500?
Not yet. SpaceX listed on Nasdaq on June 12, 2026 at $135 a share and joined the Nasdaq-100 on July 7, 2026. S&P Dow Jones Indices decided on June 4, 2026 to keep its seasoning and profitability rules for the S&P 500, so SpaceX cannot be added before it has traded for twelve months.
What stocks are in a space index?
The US-listed companies whose main business is space fall into four groups: launch (SpaceX, Rocket Lab, Firefly), connectivity from orbit (AST SpaceMobile, Iridium, Globalstar, Viasat, EchoStar), Earth imaging and data (Planet Labs, BlackSky, Spire) and spacecraft, stations and lunar landers (Redwire, Intuitive Machines, Voyager, MDA Space). Funds add suppliers and defense companies around them.
Can I build my own space ETF?
You can build the same exposure without a fund. Choose the space stocks and a SpaceX weight, backtest the basket against the S&P 500 and against the funds, then buy the shares at your broker, where there is no expense ratio. Fidelity Basket Portfolios charges a flat $4.99 a month to hold up to 50 stocks as one basket.
Sources
Expense ratios, assets and holdings from each issuer, read October 1, 2026: roundhillinvestments.com (MARS), temaetfs.com (NASA), vaneck.com (WARP), globalxetfs.com (ORBX), ssga.com (ROKT), ARK's daily holdings file (ARKX) and baroncapitalgroup.com (RONB). Procure's site could not be read, so UFO holdings and assets are from its Form N-PORT for July 31, 2026 on sec.gov. Fees and strategies from each fund's summary prospectus (Form 497K). SpaceX listing terms from its final prospectus (Form 424B4, June 12, 2026), first day trading and the Nasdaq-100 addition from Nasdaq, shares outstanding from its Form 10-Q for June 30, 2026, and the S&P 500 rule decision from S&P Dow Jones Indices' June 4, 2026 release. Vanguard weights from Vanguard's holdings as of August 31, 2026. Exchange listings from the SEC company ticker file. Space pure play shares are our own sums of the published weights; we counted companies whose main business is space and excluded defense contractors, GPS makers, component suppliers and Sirius XM. Fidelity Basket Portfolios pricing from fidelity.com. Holdings and fees change, so confirm them on the fund page before you buy. Indexes is not affiliated with any fund issuer or broker named here. We make index construction and backtesting software: we do not manage money, place trades or give investment advice, and backtested results are hypothetical.
Build the space index with the SpaceX weight you chose
Choose the names and the weights, backtest the basket against the S&P 500 and the funds, and track it every day. Then buy it wherever you invest.
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