In what was has been a sustained stretch of strength for mid-cap stocks, considering a low volatility exchange traded fund may not seem necessary.

Then again, the PowerShares S&P MidCap Low Volatility (NYSEArca: XMLV) has its advantages…and surprises. XMLV tracks the performance of the S&P MidCap 400 Low Volatility Index, which tracks 80 of the least volatile stocks from the S&P MidCap 400 Index over the last 12 months and weights holdings based on the securities’ inverse volatility, so the least volatile securities have the highest weighting. [Low Volatility Mid, Small-Cap ETFs Debut]

With mid-caps impressing this year, XMLV has lagged the S&P MidCap 400, but over the past year, there is a substantial performance gap in favor of the low volatility ETF. Over that period, XMLV is up 14.8% compared to 11.1% for the S&P MidCap 400.

Low-volatility ETFs provide investors the ability to track broad markets with some downside protection. The low-volatility strategy has a number of academic studies to support the rationale behind the investment idea, according to VIX and More, but it is better illustrated with a side-by-side comparison.

Like its large-cap cousin, the PowerShares S&P 500 Low Volatility Portfolio (NYSEArca: SPLV) has some surprises at the sector. Said another way, like SPLV, XMLV is not a veiled attempt at a utilities ETF.

“Traditionally, low volatility products have had substantial allocations to the utilities and consumer staples sectors—sectors with long histories of “unexciting” returns. However, since mid-2012, a typical low volatility portfolio has allocated less and less to utilities and consumer staples and more and more to financials, a sector with a very different set of expectations,” according to Axioma.