The U.S. dollar is a global reserve and invoicing currency, playing a major role in international debt, non-bank borrowing, and global trade. When the dollar appreciates, USD-denominated debt becomes expensive, which, in turn, disincentivizes risk-taking in financial markets. A weaker dollar has the opposite effect. As such, over the years, bitcoin and the broader crypto market have tended to move in the opposite direction of the DXY, just as stocks and gold.