CSPX vs VUAA — which S&P 500 UCITS ETF for non-US investors?

CSPX vs VUAA at a glance

Fund data from the issuers' own factsheets: iShares for CSPX (August 2026, net asset data as at 31 August 2026) and Vanguard for VUAA (31 August 2026). CSPX is also listed on several exchanges outside Europe, including Tel Aviv, Mexico and Santiago. Assets, charges, listings and share classes change — the current factsheet is the authority, not this page.

Fees: there is no fee argument

Both funds publish an ongoing charge of 0.07% a year. Not similar — the same number, from both issuers, on factsheets dated the same day. On $100,000 that is $70 a year in each case.

This is worth stating plainly because most comparisons of two ETFs resolve on fees, and this one cannot. If you arrived looking for the cheaper of the two, there isn't one. That leaves the question everyone should have been asking anyway: what actually reached the investor.

Tracking difference, and why the charge does not settle it

The ongoing charge is a published intention — what the manager takes for running the fund. The number that decides what you received is the tracking difference: the fund's realised return minus the index return, which nets the charge against securities lending income, withholding recovery, dealing costs at index rebalances, cash drag and any sampling.

A fund can charge less and still deliver less. Here, both charge the same, so the tracking difference is the only performance evidence there is — and the two funds report it against identical benchmark figures, which makes this comparison unusually clean.

Each issuer's own published figures, net of expenses, on a NAV basis. The benchmark column is identical in both documents. Since-inception figures are deliberately omitted: the funds launched nine years apart, so those two numbers cover different periods and cannot be compared with each other. Past performance is not a reliable indicator of future results.

One basis point over five years is not a ranking. It is two funds doing the same job to within measurement noise. Anyone presenting a gap that size as a reason to prefer one fund is reading precision into a number that does not have it.

Fund size and liquidity

At 31 August 2026 CSPX's accumulating share class held about US$156bn against VUAA's US$36bn — roughly four to one. Across all share classes the funds held US$159bn and US$89bn. CSPX is one of the largest S&P 500 trackers anywhere; VUAA is large by any ordinary measure. Both figures move continuously and any number quoted here will be stale before long.

Size is a proxy for two things that matter and one that does not:

• Spread, which matters. A more heavily traded line usually quotes tighter, and the spread is a real cost paid on the way in and out. It belongs to the line, not the fund — the same fund can be tight on its primary exchange and wide on a secondary listing in another currency.
• Closure risk, which matters a little. Very small funds get merged or liquidated, forcing a disposal at a time not of your choosing. Neither of these is remotely near that.
• Tracking, which it does not predict. The table above is the evidence: the fund with four times the assets delivered one basis point more over five years. Scale stopped buying efficiency long before either fund reached this size.

Spreads and where you actually trade

This is the difference most likely to cost you real money, and it is not a property of either fund — it is a property of the exchange line your broker routes to, at the moment you trade.

For a buy-and-hold investor making monthly purchases, the spread and any FX conversion on each purchase will usually outweigh a one-basis-point tracking gap many times over. The practical test is not "which fund is better" but "which line can I reach, in which currency, at what total cost". That answer depends on your broker, and it can differ between two people choosing between the same two funds.

This page deliberately quotes no spread figures. They are venue-specific, time-of-day-specific and broker-specific, and a number printed here would be wrong for most readers most of the time.

Accumulating: identical on both sides

Both funds accumulate — dividends are reinvested inside the fund rather than paid out, so nothing lands as cash, there is no reinvestment friction and nothing can be mistaken for a contribution. Neither offers an advantage here because the behaviour is the same.

Whether accumulation suits you at all is a residence question rather than a fund question: some countries tax accumulating funds on a deemed basis regardless of whether anything was distributed, and a few treat them less favourably than distributing ones. Both issuers also run distributing versions of the same exposure, so if cash dividends are what you want, that is a different share class rather than a different fund family.

Ireland, and the withholding inside the fund

Both funds are domiciled in Ireland, which is what puts the treaty rate to work. A physically replicating Irish fund suffers 15% US withholding inside the fund on the US dividends it receives, under the US–Ireland treaty, and Ireland then withholds nothing from a non-resident holder. The alternative — a US-domiciled fund — distributes US-source income taxed at your own treaty rate on the whole amount, which is 15% for many countries and 30% with no treaty or no documentation on file.

That comparison is the subject of the SPY page, not this one. Between CSPX and VUAA the treatment is identical and decides nothing. What your own country does with the result afterwards is separate again — your residence's treaty rate is a published number, and the assumptions behind the estimates are in the withholding methodology.

US estate tax

Neither fund is a US-situs asset. For a non-US, non-resident estate, US-situs holdings above USD 60,000 can attract US estate tax at rates reaching 40% on the excess unless an estate tax treaty raises that threshold — and the United States has estate treaties with relatively few countries. An Irish-domiciled UCITS sits outside that entirely.

This is one of the strongest reasons a non-US investor holds either of these funds rather than a US-domiciled S&P 500 ETF. Between the two of them it is a tie, and it should not enter the decision.

Trading currency is not currency exposure

Three different things get confused here, and they are the same for both funds.

• Underlying exposure — US companies whose shares are priced in dollars. This is what you own, in both funds.
• Share class currency — USD for both CSPX and VUAA, which is the currency the fund reports in.
• Trading currency — the currency of the exchange line you buy: USD on the LSE's dollar line, GBP on CSP1 or VUAG, EUR on Amsterdam, Xetra or Milan.

Buying the EUR-quoted line does not give you euro exposure and does not hedge anything. A euro investor holding either fund carries USD/EUR risk in full. What a line in your own currency can save is an explicit FX conversion at your broker, which on some brokers is a meaningful percentage — a transaction-cost reason to prefer a line, not a risk-management one. Neither share class described here is currency hedged; hedged S&P 500 UCITS share classes exist, cost more, and are a different product.

Exchanges and the ticker traps

Neither fund uses one ticker everywhere, and the GBP lines are where people go wrong.

Listings as published on the issuers' August 2026 factsheets. CSPX is additionally listed on exchanges outside Europe, including Tel Aviv, Mexico and Santiago. Issuers add and remove listings; the current factsheet is the authority.

The euro lines are the sharpest practical split: CSPX quotes in EUR on Amsterdam, VUAA on Xetra and Milan. Which of those your broker reaches — and whether it charges you an FX conversion to get there — is a more consequential difference than anything in the performance table. The ISIN is the identifier that does not change by venue: IE00B5BMR087 for CSPX, IE00BFMXXD54 for VUAA.

What this looks like at a broker

On a broker with broad European market access — Interactive Brokers is the usual example — both funds are reachable on several lines, and the choice collapses into three practical questions:

• Which lines does your broker actually offer? Plenty of platforms carry only a subset of European venues. A fund you cannot buy on the exchange you have access to is not a candidate, whatever its factsheet says.
• Does buying it cost you an FX conversion? Holding euros and buying the USD line means converting. On brokers with cheap FX this is a rounding error; on others it dwarfs every difference on this page.
• What does that specific line cost to trade? Commission structure plus spread, at your typical order size. A line that is cheap for a €10,000 purchase may not be for €300 a month.

Retail investors in the EEA and the UK can buy both: each publishes the PRIIPs Key Information Document, which is exactly what rules out the US-domiciled alternatives.

CSPX vs VUAA: what actually matters

Sorted by how much each term can move the outcome:

The honest summary is that this is not a fund comparison so much as a brokerage one. The two products are interchangeable to within a basis point; the costs you can actually control sit between you and the exchange. That is also why this page does not name a winner — the answer genuinely depends on an account this page cannot see.

If you are still deciding whether the Irish wrapper is right at all, that is the prior question, worked through on Irish-domiciled alternatives to SPY. And if the cheapest S&P 500 UCITS charge is what you are after, a third fund undercuts both of these — compared in SPYL vs VUAA.

See how ETF domicile affects your portfolio

The layer this page is about is invisible on a brokerage statement. Withholding suffered inside an Irish fund is deducted before the fund is paid, so it never appears on any document you receive, and tracking difference shows up nowhere except in a NAV you would have to compare against an index yourself. BorderFolio estimates the withholding per instrument, from the domicile of each fund you actually hold against the tax residence you configure, on your real dividend history rather than a worked example.

Limitations

• Fund data ages. Charges, assets, listings and share classes are as published on the issuers' factsheets dated 31 August 2026. The current factsheet is the authority.
• Tracking difference is a measurement, not a forecast. It moves with securities lending, index turnover and dealing conditions, and a one-basis-point gap is well inside the range that reverses between periods.
• Since-inception returns are not compared. The funds launched nine years apart, so those figures cover different markets.
• No spread or commission figures are quoted. They vary by venue, broker, order size and time of day, and a number here would mislead more readers than it helped.
• The second tax step is residence-specific. How your own country treats an accumulating fund, and whether it credits tax suffered inside it, is not modelled here.
• Not advice. This is an informational comparison of two fund structures, not a recommendation to buy, hold or sell either. See the investment & tax disclaimer.

Common questions

Is CSPX or VUAA better?

Neither is better as a fund. Both are Irish-domiciled UCITS ETFs tracking the S&P 500, both accumulate, both replicate physically, both are USD base currency and both charge 0.07%. Measured against the same benchmark on their August 2026 factsheets, CSPX returned 12.49% a year over five years and VUAA 12.48% — one basis point apart. What differs is scale, age and where each one lists, so the decision is about your broker and your exchange rather than about the funds.

What is the difference between CSPX and VUAA?

Three things, none of them exposure. Size: CSPX's accumulating share class held about USD 156bn at 31 August 2026 against VUAA's USD 36bn. Age: CSPX launched in May 2010, VUAA in May 2019, so CSPX has a longer published record through more market conditions. Listings: CSPX trades on the London Stock Exchange in USD and as CSP1 in GBP, and on Euronext Amsterdam in EUR; VUAA trades on the LSE in USD and as VUAG in GBP, and on Deutsche Börse and Borsa Italiana in EUR. Index, domicile, charge, structure and replication are the same.

Do CSPX and VUAA have the same TER?

Yes. Both publish an ongoing charge of 0.07% a year — iShares on the CSPX factsheet and Vanguard on the VUAA factsheet, both dated 31 August 2026. Because the headline charge is identical, the usual fee argument does not apply here at all, and the realised tracking difference is what remains to compare.

Which has the better tracking difference, CSPX or VUAA?

They are effectively level. Against the same benchmark figures, over the year to 31 August 2026 CSPX finished 0.14 percentage points above the index and VUAA 0.13; over three years both were 0.16 above; over five years CSPX 0.18 and VUAA 0.17. Differences of one basis point are noise rather than a ranking, and one measurement window is not a forecast.

Why do CSPX and VUAA both beat the S&P 500 index they track?

Because of how the benchmark is defined. Both are measured against the S&P 500 net total return index, which reinvests dividends after deducting 30% withholding tax. An Irish-domiciled fund suffers 15% US withholding on those dividends under the US–Ireland treaty, not 30%. That structural gap is worth more than the 0.07% charge, so a competently run Irish S&P 500 tracker normally finishes above its own net benchmark.

Does fund size matter when choosing between CSPX and VUAA?

Less than it looks. CSPX is roughly four times the size of VUAA's accumulating share class, and both are far past the point where scale still buys tracking efficiency or where closure is a concern. Size matters mainly as a proxy for how tightly a specific exchange line quotes — and that is a property of the line your broker routes to, not of the fund as a whole.

Do CSPX and VUAA have different US estate tax exposure?

No. Both are Irish-domiciled UCITS funds, so neither is a US-situs asset for US estate tax purposes. That is one of the main reasons non-US investors hold either of them instead of a US-domiciled S&P 500 ETF, where US-situs holdings above USD 60,000 can attract US estate tax for a non-US, non-resident estate unless a treaty raises the threshold. Between these two funds the estate question is identical and decides nothing.

Does buying the EUR or GBP line change my currency exposure?

No. Both funds hold US shares priced in dollars and both use USD as the share class currency. The currency of the exchange line you buy is the currency you transact in, not the currency of the assets — buying the EUR-quoted line of either fund leaves your economic exposure in US dollars. A line quoted in your own currency can still save an explicit FX conversion at your broker, which is a cost question rather than a risk one. Neither share class described here is currency hedged.