The fact that, under the gold standard, the value of each currency was fixed in terms of gold implied that the rate of exchange between any two currencies within the gold standard system was likewise fixed. As with any system of fixed exchange rates, the gold standard was subject to speculative attack if investors doubted the ability of a country to maintain the value of its currency at the legally specified parity. In September 1931, following a period of financial upheaval in Europe that created concerns about British investments on the Continent, speculators attacked the British pound, presenting pounds to the Bank of England and demanding gold in return. Faced with the heavy demands of speculators for gold and a widespread loss of confidence in the pound, the Bank of England quickly depleted its gold reserves. Unable to continue supporting the pound at its official value, Great Britain was forced to leave the gold standard, allowing the pound to float freely, its value determined by market forces.

With the collapse of the pound, speculators turned their attention to the U.S. dollar, which (given the economic difficulties the United States was experiencing in the fall of 1931) looked to many to be the next currency in line for devaluation. Central banks as well as private investors converted a substantial quantity of dollar assets to gold in September and October of 1931, reducing the Federal Reserve's gold reserves. The speculative attack on the dollar also helped to create a panic in the U.S. banking system. Fearing imminent devaluation of the dollar, many foreign and domestic depositors withdrew their funds from U.S. banks in order to convert them into gold or other assets. The worsening economic situation also made depositors increasingly distrustful of banks as a place to keep their savings. During this period, deposit insurance was virtually nonexistent, so that the failure of a bank might cause depositors to lose all or most of their savings. Thus, depositors who feared that a bank might fail rushed to withdraw their funds. Banking panics, if severe enough, could become self-confirming prophecies. During the 1930s, thousands of U.S. banks experienced runs by depositors and subsequently failed.