Potential Disadvantages of ETFs to Watch For
ETFs are not perfect. Here are the real downsides, risks, and situations where another investment vehicle might be better.
Don't have time? Here's what you need to know:
- 1Bid-ask spreads are a hidden cost on niche ETFs — stick with high-volume funds to minimize them
- 2Intra-day trading makes it too easy to react emotionally — automate and check quarterly
- 3Tracking error is tiny for mainstream index ETFs (0.03-0.05%) but can be larger for niche products
- 4The biggest ETF risk is behavioral: over-trading and over-complicating your portfolio
The Hidden Cost: Bid-Ask Spreads
Every ETF has a bid (price buyers will pay) and an ask (price sellers want). The difference is the spread — an invisible transaction cost. For VTI and VOO, the spread is about $0.01 per share. On a $10,000 purchase, that is roughly $0.40 — irrelevant. But for small or niche ETFs, spreads can be $0.10-0.50 per share, costing you 0.05-0.20% per trade.
Mutual funds avoid this problem entirely — they trade at the exact net asset value (NAV) once per day. For illiquid ETFs, a mutual fund equivalent may actually be cheaper to trade.
The Temptation to Trade Too Much
Because ETFs trade like stocks, they make it easy to buy and sell throughout the day. This is a feature for traders and a bug for long-term investors. Research from Barber and Odean found that the more frequently investors trade, the worse their returns. The average individual investor underperforms the market by about 1.5% per year — largely due to ill-timed buying and selling.
Mutual funds, with their once-per-day pricing, naturally discourage day-trading behavior. If you find yourself checking your ETF prices hourly and making emotional trades, the mutual fund wrapper might save you from yourself.
Other Disadvantages
Tracking error: ETFs do not perfectly replicate their index. VTI returns 9.97% when the index returns 10.00% — the 0.03% gap is the expense ratio. Larger tracking errors occur with international ETFs, leveraged products, and commodity funds that use futures.
No automatic investing at all brokers: mutual funds allow exact-dollar automatic investments at every fund company. ETF automatic investing depends on your broker's features. Vanguard does not offer fractional ETF shares, making automatic ETF investing awkward there.
Over-diversification temptation: with 3,000+ ETFs available, it is easy to own too many. Some investors hold 15-20 ETFs that overlap heavily, creating a complex portfolio that performs identically to VTI — but with higher total fees and rebalancing headaches.
Important: The biggest ETF disadvantage is not structural — it is behavioral. ETFs make it too easy to check prices, panic during drops, and trade based on emotion. Set up automatic monthly purchases and check your portfolio quarterly, not daily.
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Frequently Asked Questions
Should I avoid ETFs because of the bid-ask spread?
No — for liquid ETFs (VTI, VOO, SPY), the spread is under $0.01 per share. It is only a concern for small, niche, or thinly-traded ETFs. Stick with high-volume funds and the spread is irrelevant.
Can ETF tracking error be significant?
For mainstream index ETFs, tracking error is typically less than 0.05% per year — essentially the expense ratio. For international ETFs with withholding taxes or commodity ETFs using futures, tracking error can be larger (0.10-0.50%). Check the fund's annual report for actual vs index returns.
Are mutual funds ever better than ETFs?
In a few situations: when you invest at Vanguard and want automatic exact-dollar investments, when your 401(k) only offers mutual funds, or when you know intra-day trading access would tempt you to make emotional decisions.
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Alex Harrington
CFA Level II Candidate, Finance & Economics
Alex Harrington is an independent ETF researcher and personal finance writer with over 8 years of experience analyzing exchange-traded funds. A CFA Level II candidate with a background in economics, Alex has reviewed 800+ ETFs and helped thousands of beginners build their first investment portfolios through clear, jargon-free education.
This content is for educational purposes only and does not constitute financial advice. Past performance does not guarantee future results. Consult a licensed financial advisor before making investment decisions.