European Central Bank supervisors are asking some of the region’s lenders to assess their need for U.S. dollars in times of stress, as they game out scenarios in which they cannot rely on tapping the Federal Reserve under the Trump administration, three people with knowledge of the discussions told Reuters.

Why it matters

Nearly one-fifth of euro zone banks’ funding needs are denominated in U.S. dollars, with the lenders borrowing in markets for short-term funding that can shut down abruptly in times of financial stress. In the past, European central banks borrowed dollars from the Fed, the source of the currency, to make up for the shortfall.