Oja said that, for the banks, the interest on bank deposits at the Fed accounted for about 1.7 percent of their combined revenues.
In remarks Thursday to a Senate committee, Fed Chair Janet Yellen acknowledged the central bank is taking a look at the possibility of reversing course and potentially going to negative rates for interest on excess reserves.
"In light of the experience of European countries and others that have gone to negative rates, we're taking a look at them again, because we would want to be prepared in the event that we would need (to increase) accommodation. We haven't finished that evaluation. We need to consider the institutional context and whether they would work well here. It's not automatic," she said, adding, "we wouldn't take those off the table, but we have work to do to judge whether they would be workable here."
On Friday, New York Fed President William Dudley said he thinks it is "premature" for the central bank to start talking about a rate reversal.
Read MoreYellen on negative rates: 'We wouldn't take those off the table'
Deutsche Bank chief U.S. economist Joseph LaVorgna said he believes a return to quantitative easing is less likely than a move to negative interest rates. But his assessment of NIRP's impact on Wall Street banks is not rosy.