What Is a Mutual Fund's Turnover Ratio?
Two funds can hold similar-looking investments and still behave very differently depending on how much buying and selling happens inside them, and turnover ratio is the number that captures that activity.
The short answer
A turnover ratio measures how much of a mutual fund’s holdings were bought and sold over a given year, typically expressed as a percentage of the fund’s average assets. A turnover ratio of 100 percent roughly means the fund replaced the equivalent of its entire portfolio over the course of the year, while a ratio of 20 percent suggests a much more static, buy-and-hold approach. It’s disclosed in a fund’s prospectus and other regulatory filings, since it’s a required piece of information for investors evaluating a fund.
What drives a high or low number
Turnover reflects the fund’s underlying strategy. Index funds designed to track a benchmark tend to have low turnover, since they only trade when the underlying index itself changes its holdings. Actively managed funds, where a manager is making ongoing decisions about what to buy and sell in pursuit of outperforming a benchmark, often have higher turnover, though the range varies enormously by fund and strategy. Neither high nor low turnover is inherently good or bad on its own — it’s a reflection of approach, not a quality score.
Why turnover has a cost
Trading isn’t free. Each transaction inside a fund can generate brokerage costs and, in a taxable account, potentially realize capital gains that get passed through to shareholders even if they didn’t personally sell anything. A fund with high turnover held in a taxable brokerage account can generate a meaningful annual tax bill purely from internal trading activity, separate from whatever the investor does with their own shares. This is one of the less visible costs of fund ownership, since it doesn’t show up as clearly as the expense ratio does on a fee summary.
How it connects to the expense ratio
Turnover and expense ratio are related but distinct. The expense ratio covers a fund’s ongoing management and administrative costs, generally as a fixed annual percentage. Turnover-related trading costs are typically not included in that figure at all — they’re a separate cost embedded in the fund’s returns, harder to spot without digging into the fund’s disclosures. A fund with a modest headline expense ratio can still carry meaningful internal trading costs if its turnover is high, which is part of why looking only at the expense ratio can miss part of the full cost picture.
Weighing turnover against strategy and goals
A high turnover ratio isn’t automatically a problem if it reflects a strategy the investor deliberately chose and understands, and a low one isn’t automatically ideal if the fund’s underlying approach doesn’t otherwise fit the goal. What matters is whether the turnover level, and the costs that come with it, align with what an investor is actually trying to achieve — long-term, low-cost broad exposure typically pairs naturally with low turnover, while more tactical strategies may accept higher turnover as a tradeoff for their approach.
What to weigh
Turnover ratio is a window into how actively a fund trades internally, and that activity has real costs — trading expenses and potential tax consequences — that don’t always show up as clearly as a headline fee. Comparing turnover alongside the expense ratio and overall strategy gives a fuller picture of what a fund actually costs to hold, which depends on the specific fund and the account it sits in rather than any single number in isolation.