📅 Last updated: 8 May 2026
· 🏷 Topic: Sector ETF, themed ETF, technology, clean energy
· 🇧🇪 For: Belgian investors
In addition to broad world-index ETFs, there are sector ETFs (one economic sector) and themed ETFs (a specific theme). For Belgian investors they can be interesting as a satellite position on top of a diversified core portfolio.
Sector ETFs
Track a single sector — e.g. technology, healthcare, financials.
Well-known examples:
- iShares S&P 500 Information Technology (Nasdaq tech)
- iShares MSCI World Health Care UCITS (global healthcare)
- Xtrackers MSCI World Financials UCITS (financials)
- iShares MSCI World Energy UCITS (energy)
TER: typically 0.15-0.3%.
Belgian TOB: depends on Belgian registration — verify via FSMA or tobcalc.com.
Themed ETFs
Track a specific theme — often overlapping several sectors.
Well-known examples:
- iShares Global Clean Energy (ICLN) — renewable energy worldwide
- WisdomTree Cybersecurity — cybersecurity
- HAN-GINS Innovative Technologies — innovation / AI / robotics
- VanEck Semiconductor — chip-makers
- iShares Healthcare Innovation — biotech + medtech innovation
TER: typically higher — 0.3-0.7% (vs 0.07-0.2% for broad index).
Pros and cons
Pros:
- ✅ Concentration in a growth theme — if the theme performs strongly, higher returns than the broad index.
- ✅ Personal conviction — those with a strong belief in clean energy, AI, or biotech can express it.
Cons:
- ❌ Higher risk — concentrated by sector or theme.
- ❌ Higher TER — eats into returns.
- ❌ Timing risk — themes often move in cycles (clean energy rally 2020, crash 2022).
- ❌ “Theme drift” — what is held inside the ETF can change, often to chase momentum.
Practical allocation
For those who want a sector/themed ETF:
- Maximum 5-10% of the portfolio in any single sector/theme.
- Don’t put all satellite positions in one theme — diversification remains important.
- Be aware of the TER — at 0.5% TER over 30 years = ~15% less final capital vs 0.15% TER.
E.g. an 80% world index + 10% clean energy + 5% biotech + 5% cash is one possible pattern. The equity portion remains ~95%.
Common mistake
FOMO-driven thematic investing. “Everyone is talking about AI, I have to buy an AI ETF.” Often bought after the rally (high), sold in the crash (low). Themed ETFs are mainly suited for those who believe in a theme for 5+ years — not for those who chase the news.
Belgian taxation
Identical to other ETFs:
- TOB depends on Belgian registration (0.12-1.32%).
- Withholding tax on dividends (30% on distributing funds).
- No Reynders tax — most sector/themed ETFs are pure equities.
- Since 2026: capital gains tax of 10% above the €10k exemption on sale.
What does the research say?
Research (Morningstar, S&P) shows:
- Themed ETFs have on average lower long-term returns than broad indices, after costs.
- Survivorship bias is strong — poorly performing themed ETFs are closed and removed from the dataset.
- Those who buy a theme after a rally (FOMO) often perform worse than those who invest consistently in a broad index.
💡 For most Belgian retail investors: one world-index ETF as the core, possibly a small percentage in 1-2 themes you genuinely believe in. Don’t build your entire portfolio on a single theme.
🔗 See World ETF top choices and Diversification explained.
The Belgian cost trap in thematic ETFs
Thematic funds are usually judged on TER — often 0.40% to 0.65%, against 0.20% for a broad world index. That gap is real, but in Belgium it is rarely the largest one.
Thematic and sector ETFs are predominantly accumulating, and many are registered in Belgium. That places them in the 1.32% stock-exchange tax band, while a distributing broad index fund sits at 0.12%. That is a factor of eleven, paid on every purchase.
Worked example. €100 a month into a satellite position: at 1.32% that is 12 × €1.32 = €15.84 a year in stock-exchange tax. The same €1,200 in a fund at 0.12%: €1.44. The €14-plus difference exceeds the TER difference on that same amount (0.45% of €1,200 ≈ €5.40).
The lesson is not that thematic ETFs should be avoided, but that in Belgium the entry cost is the decisive expense for small, regular purchases — precisely how satellite positions are usually built.
Practical consequence
- Buy satellites in larger, less frequent blocks. The tax is proportional, but a tiered broker tariff rewards fewer, bigger orders.
- Check FSMA registration per ISIN before buying. Two thematic ETFs on the same theme can fall in different bands.
- Build the entry cost into your return expectation. A theme has to make up 1.32% before it draws level with a broad fund at 0.12%.
Sources
- iShares & Xtrackers — Sector & themed ETF factsheets
- Morningstar — Themed ETF performance research
- justETF — Themed ETF database
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