Two funds both charge 0.6%. One holds its positions for years; the other replaces most of its portfolio annually. Their stated costs are identical and what you actually pay is not.
Turnover — how much of a fund's holdings are bought and sold in a year — generates costs that do not appear in the expense ratio, and in a taxable account generates a tax bill you did not choose.
What changed in 2026
- Turnover disclosure improved. Fund documentation made turnover figures easier to find and compare.
- Tax-efficiency comparisons spread. After-tax return reporting became more common alongside gross figures.
- ETF structural advantages persisted. The creation and redemption mechanism continued to give most ETFs a tax-efficiency edge over traditional funds.
- Direct indexing grew. Strategies harvesting losses at the individual holding level made tax cost a mainstream topic.
What the expense ratio excludes
| Cost |
In the expense ratio? |
| Management fee |
Yes |
| Administrative costs |
Yes |
| Bid-ask spreads on fund trades |
No |
| Market impact of large trades |
No |
| Brokerage commissions |
Usually not |
| Capital gains distributed to you |
No — that is your tax bill |
The first two are the disclosed cost. The rest scale with turnover and are borne by the fund's returns or by your tax return.
Spreads are the direct one: every trade the fund makes pays the spread, and a fund replacing its whole portfolio annually pays it on everything, twice — see the bid-ask spread.
Market impact matters for large funds. Buying a meaningful position moves the price against you, which is a real cost that never appears anywhere.
The tax cost
The larger issue for taxable investors, and it is genuinely under-appreciated.
When a fund sells a holding at a gain, that gain is generally distributed to shareholders, who owe tax on it — regardless of whether you sold anything, regardless of whether the fund's value went up, and regardless of how long you held.
A high-turnover fund therefore generates a taxable event for you every year. A low-turnover fund defers gains until you sell, which means they compound untaxed in the meantime and may eventually be taxed at long-term rates.
Over a long holding period that difference compounds substantially. It is a large part of why index funds outperform comparable active funds after tax by more than they do before tax.
The perverse case: a fund can distribute gains in a year when its value fell, if it sold appreciated positions during the year. Investors receive a tax bill on a losing investment.
Where it matters and where it does not
In a taxable account, turnover matters considerably. Both the trading costs and the tax drag apply.
In a tax-advantaged account, the tax cost disappears entirely. Distributions are not currently taxable, so turnover only costs you through trading friction, which is much smaller.
That asymmetry is the basis of asset location: put high-turnover, tax-inefficient holdings in tax-advantaged accounts and tax-efficient ones in taxable accounts — see asset location vs asset allocation.
The other structural point is that ETFs are generally more tax-efficient than traditional mutual funds with similar turnover, because their creation and redemption mechanism allows appreciated holdings to leave the fund without realising gains. That structural difference frequently matters more than the turnover figure itself.
Common mistakes
- Comparing funds on expense ratio alone. Omits trading and tax costs.
- Ignoring turnover in a taxable account. Where it matters most.
- Worrying about turnover in a retirement account. Tax cost does not apply there.
- Buying a fund late in the year without checking distributions. Immediate tax bill on gains you did not participate in.
- Assuming a fund losing value cannot distribute gains. It can.
- Ignoring the fund structure. ETF versus mutual fund matters independently of turnover.
FAQ
What turnover figure is high?
Index funds are typically very low; actively managed funds vary from moderate to complete annual replacement. The comparison that matters is against similar funds rather than an absolute threshold.
How do I see a fund's tax cost?
Some providers publish after-tax returns alongside pre-tax. Distribution history is also informative — a fund distributing large gains annually is generating tax bills.
Does an index fund never distribute gains?
Rarely and not never — index changes and redemptions can force sales. Considerably less than an active fund, which is the point.
Should I sell a tax-inefficient fund I already hold?
Selling realises the accumulated gain, which may cost more than staying. The calculation depends on the embedded gain and your horizon, and it is a genuine trade rather than an obvious move.
Where to go next
For placing holdings in the right account type, read asset location vs asset allocation. For the trading costs involved, the bid-ask spread, and for distribution timing, ex-dividend dates.
This is general information, not investment advice.