Who make better investors: Men or women?

When it comes to investing, men might be smart to turn everything over to women. That's because female investors make more money than men and are less likely to lose money, according to a new data analysis from portfolio platform SigFig.

Using data drawn from portfolio trackers at AOL DailyFinance, CNNMoney, USA Today and Forbes, SigFig looked at the results of 750,000 portfolios to find the difference between returns for female and male investors. In 2014, women earned median net returns of 4.7 percent, versus 4.1 percent for men, a 12 percent difference. Those results mean women with $100,000 to invest over 30 years would make $58,000 more than a man, even though women tend to own more expensive funds.

Among investors who made their own trades, 64.6 percent of women trailed the S&P 500's performance, although they still made money. For men, the figure was 58.5 percent.

Men outdo women in two ways. One was in losing money: 25.8 percent of men's portfolios had negative returns, while only 20.4 percent of women's did. But more men, 15.7 percent, did beat the S&P 500's performance, compared to 14.9 percent of women.

One possible reason for the difference is account churn. Investors pay fees every time they buy or sell stock, and those fees can take a significant bite out of total returns. Women had a median portfolio turnover of 9 percent whereas men were half again as likely to be trading, creating a median 14 percent turnover.

Although men had demonstrably worse performance, they were far more confident that they could beat the results of the market. Only 11 percent of women thought they could outperform the S&P 500; 17 percent of men thought they could.

There was also a gender bias toward particular stocks. Men were more likely to hold shares of electric-car maker Tesla (TSLA), Coca-Cola (KO), Oracle (ORCL), Ford (F), Microsoft (MSFT), Walmart (WMT) and biotech firm Gilead Science (GILD).

Women preferred Frontier Communications (FTR), JPMorgan Chase (JPM), Pfizer (PFE), Kraft (KRFT), Whole Foods (WFM), Boeing (BA), Abbvie (ABBV), Merck (MRK), Amazon (AMZN) and Google (GOOG).

Men and women had an equal interest in Apple (AAPL).