What is included in the supply of US dollars in the market for foreign-currency exchange in the open-economy macroeconomic model?

In the open-economy macroeconomic model, the supply of US dollars in the foreign-currency exchange market includes the dollars held by domestic consumers and businesses, as well as those held by foreign entities. It encompasses the dollars available for trade in the foreign exchange market, which can be influenced by factors such as foreign investment in the U.S., exports, and remittances. Additionally, actions by the Federal Reserve, such as open market operations, can also affect the overall supply of dollars in circulation.