ETF základy
Smart Beta and Factor ETFs: What to Expect — and When They (Don't) Make Sense
Key takeaways
- Smart beta (factor) ETFs track indices built on specific rules — selecting stocks based on value (P/E, P/B), momentum, size, quality, or low volatility.
- Academic research (Fama-French) documents the existence of factor premiums — but premiums are not guaranteed and may arrive with a decade-long delay.
- The value factor underperformed the market throughout 2010–2020, before recovering strongly in 2021–2022 — investors who didn't stay the course missed the premium.
- Factor ETFs typically have higher TERs (0.2–0.5%) than market ETFs (0.07–0.2%) and higher portfolio turnover — which reduces real returns.
- Factor ETFs make sense as a satellite addition to a core portfolio for investors with a 10+ year horizon and the ability to endure multi-year factor underperformance.
Smart beta ETFs (or factor ETFs) track indices built on specific rules — not by market capitalization, but by selecting stocks with certain characteristics such as low valuation, high momentum, or strong balance sheet quality. They are a bridge between passive and active investing.
The main factors and their rationale
- Value: stocks with low P/E or P/B (Price-to-Book). Thesis: the market overprices hype and underprices boring companies — historically these stocks have outperformed the market over the long run.
- Momentum: stocks that have risen most in the past 6–12 months. Thesis: market trends persist longer than would be "rational."
- Quality: companies with high return on equity (ROE), low debt, and stable earnings. Thesis: quality companies outperform the market especially during recessions.
- Low Volatility: stocks with historically lower volatility. Paradoxically, they outperform theory — lower-risk stocks tend to have better risk-adjusted returns.
- Size: small-cap stocks have historically outperformed large caps, but with higher volatility.
Why factors don't always work — and why that matters
Factor premiums are not guaranteed. The value factor underperformed the market (S&P 500) for almost an entire decade from 2010 to 2020. Investors who abandoned value ETFs in 2019 or 2020 after a decade of underperformance missed the strong recovery in 2021–2022. The most important lesson: factor premiums exist, but they arrive irregularly and with long gaps.
When factor ETFs make sense
As a satellite position (10–20% of portfolio) for investors with a significantly longer horizon (15+ years) and the emotional resilience to endure multi-year underperformance. Never as a replacement for a core position in a market ETF. The core portfolio and its composition are discussed in the article how to build your first portfolio.
Practical selection of a factor ETF
Look for UCITS funds with Irish domicile tracking MSCI World Factor, MSCI World Value, or S&P 500 Enhanced Value indices. TERs are typically 0.2–0.5% — verify whether the historical factor premium has compensated for higher fees. Detailed comparisons can be found in the ETF section. If you're looking for an alternative to a purely passive approach, also check out dividend aristocrats — a different method of stock selection with a historically proven rationale.
Disclaimer: this text is not investment advice. Past returns are not a guarantee of future results.
FAQ
What are factor ETFs and how do they differ from a market index?
Factor ETFs (smart beta) track indices built on specific rules — value, momentum, quality, size, or low volatility — rather than market capitalization. The aim is to capture academically documented factor premiums above the market index return.
Are factor premiums reliable?
Not always and not in the short term. The value factor underperformed the S&P 500 for almost an entire decade (2010–2020). Premiums exist but arrive irregularly, with periods of underperformance lasting 7–10 years. An investor must be prepared to stay the course.
How much of a portfolio should go into factor ETFs?
The standard guidance (which is not investment advice) is factor ETFs as a satellite position of 10–20% for investors with a horizon of 15+ years. The core of the portfolio should be a market ETF with a low TER.