In its annual stress test for 2016, the Fed said it will assess the resilience of big banks to a number of possible situations, including one where the rate on the three-month U.S. Treasury bill stays below zero for a prolonged period.
Not because they think the economy is in trouble or anything.
"This scenario does not represent a forecast of the Federal Reserve," the central bank said. It also assumes "that the adjustment to negative short-term rates proceeds with no additional financial market disruptions."
I’m sure it means nothing.