Best Performing UCITS ETFs — and Why That's the Wrong Question

Top-performing UCITS ETFs Irish investors can buy

The following table is illustrative — it reflects categories that have consistently topped UCITS performance rankings over 5 and 10 year periods to early 2026. Individual fund returns vary year to year; the table groups them by underlying strategy, which is what matters for forward thinking. All funds are Irish-domiciled UCITS unless flagged.

Returns approximate, in USD or EUR base, gross of Irish Exit Tax. Source: each fund's published factsheet, January 2026. Past performance is not a guarantee of future returns and does not include investor-level Irish 38% Exit Tax. Do not treat as a buy list.

Why "buy the winner" loses money on average

Three independent bodies of research point at the same finding from different angles:

• 1
  Morningstar's annual Mind the Gap study. Compares the time-weighted return of funds with the dollar-weighted return investors actually capture. The "gap" — caused by buying after rallies and selling after drops — has averaged about 1.5 percentage points a year across US-equity funds for the past decade.
• 2
  S&P's SPIVA Persistence Scorecard. Tracks how often top-quartile funds remain top-quartile in subsequent years. Across virtually every category and time horizon, the answer is "no better than random". A top-quartile equity fund has roughly a 25% probability of staying in the top quartile over the next 5 years — exactly the result you'd get by chance.
• 3
  Vanguard's flow research. Investors persistently move money into the strategies that have just done well and out of those that have just done badly — exactly the opposite of mean reversion. Vanguard's data, going back decades, shows that this behaviour pattern systematically destroys returns net of asset allocation choices.

The structural mechanism is simple: high recent returns push valuations up. High valuations mathematically imply lower expected forward returns. Buying the recent winner means buying expensive. The boring counter-strategy — broad global market exposure at low cost, held continuously — sidesteps the trap by definition.

The Irish Exit Tax angle that makes it worse

For an Irish investor, performance-chasing has a uniquely expensive feature: every time you sell one ETF to switch into another, you trigger a 38% Exit Tax event on any gain. Ordinary share investors at least get a €1,270 annual CGT exemption and loss-offset relief. You don't.

Worked example: you bought CSPX five years ago, it's up 70%, and you decide to switch into the latest hot semiconductor ETF. On a €30,000 holding sitting on €12,500 of gain, switching costs you €4,750 of Exit Tax — money that was previously compounding inside your portfolio and now belongs to Revenue. The new fund needs to outperform CSPX by ~16% just to make you whole on the switch.

For Irish investors, the correct response to the urge to chase performance isn't only behavioural — it's also tax-mathematical. Buy and hold beats trade-and-time, by even larger margins than for US or UK investors who don't pay Exit Tax on every disposal.

What to actually use to pick an ETF

Drop "1-year return" from your evaluation criteria. The six things that matter for an Irish investor:

1. 1 Irish domicile (IE ISIN). Cuts US dividend withholding from 30% to 15% under the treaty. Compounds for as long as you hold.
2. 2 Accumulating (Acc) share class. Defers Exit Tax until disposal — better than annual taxation on distributions.
3. 3 Total Expense Ratio under 0.30%. Anything above that for a core market-cap-weighted fund is a fee you don't need to pay. Under 0.10% is achievable for S&P 500 / MSCI USA.
4. 4 Fund size above €100m and tight bid-ask spread. Below that, liquidity risk and wider spreads start to matter — particularly if you ever need to sell quickly or in size.
5. 5 Index methodology you actually want. Does the index reflect the exposure you're aiming for — or just whatever name sounds appealing? "Disruptive innovation" and "AI" theme funds rarely deliver the exposure their marketing implies.
6. 6 Tracking difference, not 1-year return. A good ETF tracks its index closely (within 0.10–0.20% per year). That's the operational quality measure — past returns are mostly the index doing what indexes do.