Even when controlling for factors such as income, a FINRA study has found that white households are more likely than either black or Hispanic households to have a taxable investment account.

The study, “A Snapshot of Investors in America,” from the FINRA Investor Education Foundation, found that while about 6 out of every 10 U.S. households have securities investments, whether through taxable accounts, IRAs, or employer-sponsored retirement plans, that number drops substantially when only taxable accounts are considered—to just over 3 out of 10.

Read: African Americans list saving as top financial goal

Those households owning taxable investment accounts, said the study, “are more likely to be older, affluent, college educated and white relative to households with only retirement accounts or households without investment accounts. They also have much higher levels of financial literacy and moderately higher risk-tolerance levels.”

Blacks and Hispanics, the study added, are among the demographic groups “significantly underrepresented among investor households … although these differences narrow after controlling for factors such as income, education, and age.”

Data from a 2012 study of more than 25,000 households revealed that “when everything else is equal, black households were still 7 percentage points less likely to have taxable investment accounts than white households; and Hispanic households were 4 percentage points less likely to have such taxable accounts than white households.”

Read: RIAs not in minorities' American Dream

Other characteristics of the one third of households with taxable accounts included the fact that those with incomes higher than $50,000 annually were 22 percent more likely to have such an account than households with lower incomes.

In addition, college degrees, greater financial literacy, and a higher tolerance for risk were also common characteristics.

Households with dependents were also less likely to have a taxable investment account than were households consisting only of a couple.

The study said that 33 percent of U.S. households have taxable investment accounts; 29 percent have only tax-favored retirement accounts; and 38 percent have neither.