Buying a little of everything pays off, according to a recent survey of almost 350 advisor-submitted model portfolios conducted by Boston-based Natixis Global Asset Management.

In its second quarter “Portfolio Clarity Trends Report,” Natixis found that the most broadly diversified portfolios performed best during the period.

From the August 18, 2015, market peak through June 30, 2016, the returns of the most diversified, best-performing portfolios in Natixis’s analysis grew by 2.7 percent, exceeding the bottom quartile portfolios by 340 basis points.

“Diversification matters,” said Marina Gross, executive vice president of Natixis’s Portfolio Research and Consulting Group, in a statement. “In an environment distinctly lacking in precedent and visibility, diversification may be one of the best defenses an asset allocator has.”

Natixis said that diversification meant including a healthy allocation to alts, which the company said were being used at their greatest level in three years.

An average moderate-risk portfolio analyzed by Natixis gained 2.1 percent in the second quarter, outperforming the average retail portfolio, which grew only 0.5 percent, and nearly matching the 2.5 percent performance of the S&P 500.

The average moderate risk portfolio had an 8 percent average alternatives allocation in the second quarter of 2016, up from 6 percent in the same period in 2015. Among the 66 percent of 2016 portfolios using alternative funds, the average weight was 11 percent.

The moderate risk portfolio benefited from an allocation to a mix of alternative strategies and fixed-income investments, said Natixis. Year over year, the average moderate risk portfolio had fewer assets allocated to stocks in the second quarter of 2016, 52.7 percent, than they did during the same period in 2015, when they were at 54.8 percent. Bond allocations, on the other hand, were up by 3 percentage points, from 27 percent in the second quarter of 2015 to 30 percent this year.

The best-performing portfolios through the second quarter had lower allocations to equity and higher allocations to fixed income and alternatives.

The best diversification drivers were managed futures, gold, market neutral and long duration world government bonds, according to the research.

American advisors favored domestic stocks over international stocks, but remained highly concentrated in equities, which contributed 92 percent of the overall portfolio risk.

Diversification to and within alternatives helped lessen the severity of recent equity market drawdowns, like the market shock following the U.K.’s vote to leave the European Union.

Portfolios well positioned ahead of the late-June Brexit referendum proved more resilient during the market aftershocks that followed, according to Natixis.

For its analysis, Natixis’s Portfolio Research and Consulting Group analyzed 350 portfolios on behalf of financial advisors to determine which strategies worked and which didn’t.

Natixis’s report tracked the allocations and performance of 347 moderate model portfolios submitted by U.S. financial advisors from January 2016 through June 2016, part of a broader sample of 2,290 portfolios submitted in the three-year period from January 2013 to June 2016. The retail investor average portfolio is a benchmark constructed from 50,000 retail investor portfolios.