As market volatility spiked, investors who continued to view U.S. stock markets in a favorable light looked to a low-volatility exchange traded fund strategy to diminish further risks ahead and still keep a foot in the game.

The iShares MSCI Min Vol USA ETF (Cboe: USMV), the largest US-listed low volatility exchange traded fund, was among the most popular ETF plays over the past month, attracting $1.1 billion in net inflows, according to XTF data.

“This fund doesn’t directly target stocks with low volatility, though it still heavily favors them. It considers both expected individual stock volatility and correlations across stocks, under a set of constraints, like limiting sector tilts. This holistic approach causes the fund to own some more-volatile stocks than it would if it simply targeted the least-volatile stocks in the market. However, it should lead to a better-diversified portfolio that can translate into lower risk at the portfolio level,” Morningstar’s Alex Bryan said in a research note.

USMV select stocks based on variances and correlations, along with other risk factors. The low or minimum volatility strategy targets stocks that have lower expected risk or less idiosyncratic risks. Specifically, the strategy targets equities that exhibit lower beta, a measure of volatility or systematic risk of a security to that of the overall market. Consequently, minimum volatility portfolios are constructed with stocks that exhibit lower market risk or beta.