ETF Costs: How Expense Ratios, Spreads, and Commissions Affect Your Returns

Expense Ratio: The Biggest Cost Over Time

The expense ratio is the annual fee expressed as a percentage of assets under management. It covers fund management, administration, marketing, and operational costs. For passive index ETFs, expense ratios range from 0.01% (FXAIX, though technically a mutual fund) to 0.75% for thematic ETFs. For active ETFs, expense ratios range from 0.35% (JEPI) to 0.99% (ARKK, COWZ). The impact compounds over time. A 0.10% difference on $100,000 over 30 years at 7% returns costs approximately $10,000 in reduced ending wealth. When choosing between ETFs tracking the same index, always pick the one with the lowest expense ratio. VOO (0.03%) vs IVV (0.03%) vs SPY (0.09%) — the choice is clear: VOO or IVV save $60/year per $100,000 over SPY. Learn about index fund fees.

Bid-Ask Spread: The Cost of Trading

The bid-ask spread is the difference between the highest price a buyer is willing to pay (bid) and the lowest price a seller is willing to accept (ask). For popular ETFs like VOO, SPY, and IVV, the spread is typically $0.01 to $0.03 per share — essentially negligible (0.01% or less). For less liquid ETFs — thematic funds, small-cap ETFs, international ETFs, or bond ETFs — spreads can be $0.10 to $0.50 per share, which is 0.10% to 0.50% per trade. Since you pay the spread on both purchase and sale (round trip), a 0.20% spread costs 0.40% round trip. If you hold for 5 years, that is 0.08% per year — significant on top of the expense ratio. Use limit orders to control spread costs. Never use market orders for illiquid ETFs.

Commissions: Mostly Eliminated but Still Relevant

Since 2019, most major US brokers (Vanguard, Fidelity, Schwab, Robinhood, E*TRADE, Interactive Brokers) offer commission-free trading on US-listed ETFs. This has effectively eliminated commissions as a significant cost for retail investors. However, commissions still exist in some situations: trading non-US ETFs on foreign exchanges (ETFs listed in London, Hong Kong, or Tokyo may have commissions), trading through some international brokers, and trading certain niche or inverse/leveraged ETFs. Even commission-free trading has hidden costs: order flow payment (PFOF) means your broker may route orders to market makers who profit from the spread, potentially resulting in worse execution prices. The difference is small (0.01-0.05%) but worth knowing about.

Premium and Discount to NAV

ETFs trade on exchanges at market prices that can deviate from the fund's net asset value (the actual value of the underlying securities). When an ETF trades above its NAV, it trades at a premium. When below, at a discount. For liquid, broad-market ETFs like VOO (S&P 500) or BND (total bond market), premium/discount is typically 0.01% to 0.10% and lasts minutes. For illiquid ETFs — emerging market bonds, frontier markets, thematic ETFs, or leveraged ETFs — premium/discount can exceed 1% and persist for days or weeks. During periods of market stress (March 2020 COVID crash), even liquid ETFs traded at significant discounts to NAV as market makers withdrew. Buying an ETF at a 1% premium means you start 1% behind. Check an ETF's historical premium/discount data on the issuer's website before trading.

Tracking Error: The Hidden Cost

Tracking error measures how closely an ETF's performance matches its underlying index. A perfectly tracking ETF would have zero tracking error. In reality, all ETFs have some tracking error due to fees, sampling (not holding every security in the index), securities lending, dividend timing, and index rebalancing costs. Low-cost S&P 500 ETFs like VOO and IVV typically have tracking error of 0.01-0.03% annually. Some ETFs have positive tracking error — they actually outperform their index thanks to securities lending revenue. Other ETFs, especially those using sampling or tracking complex indexes, can have tracking error of 0.20-0.50% annually. Always check an ETF's tracking difference (return vs index) on the issuer's website. The cheapest ETF is not always the best if it has higher tracking error.

Total Cost of Ownership: Putting It All Together

The total cost of owning an ETF includes expense ratio + bid-ask spread cost (annualized) + commission cost (annualized) + premium/discount cost (annualized) + tracking error. For a buy-and-hold investor holding VOO for 10 years, the total annual cost might be: 0.03% (ER) + 0.02% (spread annualized) + 0% (commission) + 0.01% (premium/discount) = 0.06% per year. For an active trader holding an emerging market ETF for 6 months: 0.30% (ER) + 0.40% (spread round-trip) + 0% (commission) + 0.50% (potential premium/discount) = 1.20% total cost annualized. The difference is enormous. For long-term investors, minimizing expense ratio is the single most important cost factor. For traders, spread and premium/discount costs dominate. Always match your holding period to the appropriate ETF cost structure.

What is a good expense ratio for an ETF?

For passive index ETFs, a good expense ratio is under 0.10%. The best S&P 500 ETFs charge 0.03%. For international ETFs, 0.05-0.15% is good. For bond ETFs, 0.03-0.10% is good. For active ETFs, expense ratios of 0.35-0.75% are typical, but you should carefully evaluate whether the active management justifies the higher cost. For thematic or niche ETFs, expense ratios can be 0.50-0.75%, and these are generally not recommended for core portfolio holdings.

Do ETFs have hidden fees?

Yes. Beyond the expense ratio, ETFs have bid-ask spreads, potential premium/discount to NAV, and tracking error. Some ETFs also charge transaction fees (rare for US brokers). Securities lending revenue can offset some costs — some ETFs actually have negative net expenses after accounting for lending revenue. The prospectus and annual report disclose all costs. Always read the fee table in the prospectus (the "fee waiver" section is particularly important) and check the fund's tracking difference on the issuer's website.

How much does a 1% expense ratio cost over 30 years?

On a $100,000 investment earning 7% annually, a 1% expense ratio reduces your ending balance from $761,226 to $574,349 — a loss of $186,877, or 25% of your potential wealth. That is why choosing the lowest-cost ETF for a given asset class is one of the most important investment decisions you can make. Over 30 years, even 0.10% in additional fees costs over $21,000 on $100,000 invested.

Are commission-free ETFs really free?

Commission-free ETFs still have expense ratios and bid-ask spreads. The commission is eliminated, but you still pay the ongoing expense ratio and the spread each time you trade. Commission-free ETFs also generate revenue for brokers through payment for order flow (PFOF), securities lending, and asset management fees. Some brokers offer "zero commission" but charge for order routing that may result in slightly worse execution prices. The total cost is still dramatically lower than the days of $7-20 per trade, but it is not literally free.

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