Portfolio Turnover: How High is Too High?

A reader writes in, asking:

“When looking at a mutual fund at what point would you say it has a high turnover ratio? For example, I have a Mid-Cap value fund that has a 39% turnover ratio. Do you think this is too high? What are your thoughts on this?”

A turnover rate doesn’t mean anything without context.

For example, Vanguard’s Short-Term Treasury Index Fund — which is entirely passive — has a turnover rate of 211% according to Morningstar. That sounds super high, but for a short-term bond fund, it’s actually quite reasonable. The bonds in the portfolio mature frequently given their short-term nature, so the fund has no choice but to frequently buy new bonds.

Of course, stocks don’t “mature” like bonds do. But, at least for index funds, there is still going to be some degree of forced turnover for a fund when a stock it is holding moves out of the targeted category. And the more specific the targeted category, the greater that level of turnover.

For example, a mid-cap value index fund would have turnover whenever a holding becomes too large or too small to be classified as mid-cap. And it would also have (less common) turnover when a stock moves from being considered “value” to being considered “growth.”

And, therefore, a mid-cap blend fund (with no value/growth tilt) would generally have less turnover than a mid-cap value fund — because the mid-cap blend fund only has one source of forced turnover (i.e., one way in which stocks can move out of the targeted category) whereas the mid-cap value fund has two. Similarly, a value fund (with no specification as to market-cap) will also generally have less turnover than a mid-cap value fund. And a “total market” type of fund would have even less natural turnover, because companies only go out of the “total market” when they cease to exist as publicly traded companies.

And these expectations are in fact borne out if we look at the turnover rates for Vanguard index funds in these categories.

• Vanguard Mid-Cap Value Index Fund has a turnover rate of 20.1%,
• Vanguard Mid-Cap Index Fund has a turnover rate of 14.8%,
• Vanguard Value Index Fund has a turnover rate of 7.8%, and
• Vanguard Total Stock Market Index Fund has a turnover rate of 3.5%.

According to the Investment Company Institute, the asset-weighted portfolio turnover rate experienced by stock-fund investors for 2015 was 44%. (The fact that this is “asset weighted” means that larger funds count more heavily in the calculation than smaller funds.) So the turnover rate of 39% mentioned by the reader for his mid-cap value fund is below average for a stock fund, despite the fact that this fund is in a category that would typically lead to higher turnover than a more broadly diversified stock fund.

That said, the turnover rate is still roughly twice that of the Vanguard index fund in the same category.

In his book Bogle on Mutual Funds, John Bogle estimates that a fund’s costs from turnover will be in the rough ballpark of 1.2% x the reported annual turnover rate. So, for example, a fund with a 100% annual turnover rate will experience a “hidden” cost of approximately 1.2% per year. But that is of course just an estimate, and the actual costs will vary from one fund category to another.