Nationwide protests have cast a spotlight on racism and inequality in the U.S. Now a major bank has put a price tag to how much the economy has lost as a result of discrimination against African Americans: $16 trillion.

Since 2000, U.S. gross domestic product lost that much as a result of discriminatory practices in a range of activities including in education or access to business loans, according to a new study by Citigroup. It's not an insignificant number: By comparison, the country's GDP totaled $19.5 trillion last year.

And not acting to reverse discriminatory practices will continue to extract a cost. Citigroup estimates the economy would see a $5 trillion boost in the next five years if the U.S. were to tackle key areas of discrimination against African Americans.

"We believe we have a responsibility to address current events and to frame them with an economic lens in order to highlight the real costs of longstanding discrimination against minority groups, especially against Black people and
particularly in the U.S.," wrote Raymond J. McGuire, a vice chairman at the bank and the chairman of its Banking, Capital Markets, Advisory team.

Wall Street itself has also faced accusations for years of discriminatory practices against African Americans, such as limiting approval for mortgages or not providing enough banking options in minority neighborhoods, which are among the damaging actions identified by Citigroup researchers.