Although women not only participate at higher rates than men and even take similar risks with the investments in their plans, they simply don’t have as much pay to draw on for savings.

The automatic enrollment feature has muddied the waters on this finding.

While at first blush, men appear to benefit more from automatic enrollment than women, the Vanguard study found that lower-wage individuals see the largest improvements from automatic enrollment—and a higher proportion of women than men have lower wages.

According to the study, women earning less than $100,000 have participation rates that are about 20 percent higher than men.

Even at incomes of $100,000 or more, women are more likely to be participants.

But what’s telling is the fact that 45 percent of the female population has wages of less than $50,000, compared with 28 percent of the male population—and approximately 60 percent more women fall into the lower-income groups than men.

Once they’re in a plan, the study found, women across all income levels save at rates that are anywhere from 7 percent to 16 percent higher than those of men.

And while there’s considerable variation in deferral rates because of factors including age, pay level, gender, tenure and plan design, deferral rates rise with wages, age, and tenure.

Auto enrollment generally brings in participants at lower deferral rates because the default is generally set at just 3 percent. But, controlling for all the variables that can determine deferral rates, the study found that women have predicted deferral rates that are 3 percent higher than men.