The record wealth gap between whites and minorities is driven inpart by how they invest in their 401(k)s, according to StanfordUniversity researchers.

The researchers, Mark Cullen, Kai Kuan and SepidehModrek, came to that conclusion after looking under thehood of one 401(k) plan, examining thedifferences in savings and investment habits between white,African American and Hispanic co-workers over an eight-yearperiod.

Typically, higher incomes, more and larger inheritances, andhigher rates of home ownership all influence wealth accumulation.But past research on how savings and investing habits affect wealthhas produced ambivalent data.

Aiming to get to the bottom of things, the Stanford academicstracked a group of workers that was continuously employed at thesame firm between 2003 and 2010.

More than 9,500 participants’ accounts were examined, noneof whom earned more than $200,000 in any given year. Theworkers spanned 29 U.S. locations. Three-quarters were hourlyworkers, and 83 percent were male. In terms of race, 83percent were white, 8.3 percent African American, and 5.8 percentHispanic.

At the end of the study period, the median 401(k) accountbalance was just over $52,500.

However, the median account balance for whites between 40and 60 was near $90,000.

For Hispanics, the median balance was near $50,000, while forAfrican Americans it was near $30,000.

Even younger whites, those ages 20 to 40, hadmedian account balances that were higher thanthe middle-age African Americans.

The disparity is explained, in part, by muchhigher rates of non-participation among both African Americans andHispanics, the researchers said.

When they do participate, Hispanics tend to defer equal amountsof income as whites. But the study showed African Americanscontributed about 2 percent less of their income to the plan thanwhites.

Minorities were also only half as likely to invest in stocks aswhites were, and twice as likely to invest in conservativemoney-market funds, clearly affecting returns on accounts, andultimately balances.

And both Hispanics and African Americans drew down their 401(k)balances through withdrawals and loans at a higher rate thanwhites, with African Americans also withdrawing much more thanHispanics.

The paper attempts to speculate how financial literacy affectssavings habits by separating data of salaried and hourly workers, a“crude” way of estimating financial literacy, admitted theresearchers.

Nonetheless, salaried African Americans were still less likelyto participate than salaried whites, whereas salaried Hispanicsparticipated at rates similar to whites.