CSPX: Why This S&P 500 ETF Remains a Core Choice for European Index Investors

Most European investors are quietly sabotaging their own wealth by picking the wrong S&P 500 ETF. The fact is, if you’re buying US exposure from this side of the Atlantic and you’re not holding CSPX, you’re almost certainly leaving money on the table—thanks to avoidable tax drag, higher costs, and senseless currency exposure. Let’s cut through the noise: CSPX remains, even approaching 2026, the best S&P 500 ETF for most European index investors. The alternatives—VUSA and SPY5—may have their fan clubs, but on the metrics that matter (after-tax returns, fees, liquidity), CSPX is still the kingpin. If you’re serious about not getting fleeced by the system, CSPX should be at the core of your portfolio. Here’s why.

CSPX: The Tax-Efficient Juggernaut

Most European investors don’t realize it, but tax drag is the silent killer of long-term returns. CSPX (iShares Core S&P 500 UCITS ETF, domiciled in Ireland) is the poster child for tax efficiency on this continent, thanks to its unique structure under the Ireland–US tax treaty.

CSPX pays just 15% withholding tax on US dividends, compared to the 30% hit suffered by most direct US-domiciled ETFs or poorly structured funds.

On €100,000 invested with a 1.5% dividend yield, that’s a difference of €225 per year—over a decade, you’re handing over thousands in unnecessary taxes if you pick the wrong fund. CSPX’s structure is a real, quantifiable advantage, not just a line in a factsheet. And yes, the regulatory picture is changing. But even with looming EU “tax harmonization” rumors for 2026, there’s zero concrete evidence that Ireland’s US treaty benefits will evaporate overnight. If anything changes, you’ll be able to pivot—until then, CSPX still delivers the best after-tax bang for your buck.

Liquidity and Fees: CSPX Still Has the Edge

Let’s talk liquidity and cost. CSPX’s daily trading volume regularly exceeds €100 million, far outpacing VUSA and SPY5. That means tighter spreads and lower friction every time you buy or sell. For retail investors, this isn’t just a nerdy detail—it’s real euros saved each trade.

As of Q1 2024, CSPX’s total expense ratio is just 0.07%, undercutting VUSA (0.07%) and SPY5 (0.09%). In absolute euro terms, on a €50,000 holding, that’s €35 per year for CSPX versus €45 for SPY5. Why pay more for a badge?

And let’s not ignore the all-important size factor. CSPX is a €70+ billion behemoth. That scale translates into lower tracking error, more resilience in times of stress, and—crucially—less risk of getting blindsided by stealthy fund closures or liquidity shortages.

The Currency and Trading Advantage for European Investors

It’s 2024. Why are European investors still dabbling in USD-denominated products when they can avoid FX headaches entirely? CSPX trades in EUR on all major European exchanges, making it ideal for anyone who earns, spends, and thinks in euros. This is a level of convenience (and risk management) that US-domiciled ETFs simply can’t match. Contrast this with VUSA and SPY5. Yes, both are UCITS-compliant and available in EUR, but VUSA’s GBP listing creates unnecessary confusion, and SPY5’s euro liquidity still lags. If you’re optimizing for the “sleep at night” factor, CSPX’s deep, liquid EUR trading is a win.

To Be Fair: The Case Against CSPX

Let’s not pretend CSPX is flawless. Critics point to three main issues: regulatory risk, fund size “too big to be nimble,” and the taxable account dilemma. First, the elephant in the room—possible changes to the Ireland–US tax treaty or EU regulations in 2026. While nothing is set in stone, there’s chatter that the EU could harmonize tax treatment, reducing CSPX’s current lead. But let’s be clear: no alternative product offers better terms today. If the legal regime does change, all UCITS S&P 500 ETFs will be impacted, not just CSPX. Second, some argue that CSPX is so massive it may be harder to maneuver in a crisis. This is a classic example of missing the forest for the trees: scale is your friend when it comes to index tracking and cost. The risk of a “run” on a €70bn ETF is laughably overblown compared to the risk of holding some under-the-radar, thinly traded S&P 500 tracker that could vanish in a regulatory footnote. Finally, the taxable vs. tax-sheltered account debate. Here’s the reality: CSPX is superb in both. In taxable accounts, its reduced US withholding tax is a direct benefit. In ISAs, SIPPs, or European pension plans, the cost advantage still applies, and the simplicity of holding a EUR-listed, widely accepted ETF streamlines portfolio admin.

Conclusion: Ignore the Hype—CSPX Is Still Your Best Bet

Let’s put the “CSPX ETF Europe 2026” debate to bed. If you want to maximize your S&P 500 returns, minimize friction, and avoid tax pitfalls, CSPX is the ETF to hold—period. Don’t get swept up by trendy newcomers or “what if” regulatory scares. If and when the rules change, you can revisit your options. Until then, CSPX should be the default for European index investors who want to win, not just participate. For a comprehensive breakdown of CSPX vs. VUSA vs. SPY5, see our analysis: Which S&P 500 ETF Should Europeans Buy in 2026?.

Ignore CSPX at your own risk. If you’re not optimizing for after-tax returns in 2024—and beyond—you’re just volunteering to be average.

My prediction? Even if regulations shift, CSPX’s lead will endure through sheer scale and efficiency. Don’t get caught flat-footed: review your holdings, cut the fat, and make CSPX your S&P 500 core until evidence—not gossip—suggests otherwise.

Disclaimer: This article reflects the author's opinion and is for educational purposes only. It does not constitute financial advice. Always do your own research before making investment decisions.