
Understanding dollar shortages and related market dynamics
A dollar shortage is a state of FX and rates markets where covered interest rate parity between the U.S. and another currency area would result in excess dollar demand. Covered interest rate parity is the equality for short-term interest rate differentials and FX forward implied carry. Since the great financial crisis, arbitrage between onshore and offshore dollar credit markets through FX swaps has been impaired. In contrast, the dollar’s dominance in international transactions has remained intact. The consequence of market segmentation and dollar dominance has been sporadic dollar shortfalls in times of market turmoil or tightening financial conditions: a rush for liquidity turns into a net “dash for dollars,” and dollar rates in the offshore market rise above those in the onshore markets. Since higher dollar rates in the offshore market drive both offshore borrowers and lenders to buy dollars in the FX spot market directly, the dollar appreciates, at least temporarily.