Many factors and not to the same degree or speed
Here is a rundown of major factors (based on an article by Finance Magnates). There are other factors, such as disease (think of the impact caused by Covid on global trade and currency flows, economic output, and travel).
Some factors will have a relatively greater impact, or act relatively less quickly, than others.
Employment (high employment supports GDP)
GDP (a strongly-growing economy is attractive so its currency appreciates)
Interest rates (higher interest rates tend to cause the currency to appreciate, e.g., the USD in 2022)
Imports versus Exports (more exports favours appreciation of the exporter's currency)
Politics (e.g., capital controls, supporting a currency, currency pegging, fiscal and monetary policies, budget deficits, austerity policies, trade deficits, public sector debt, corruption)
Environment (e.g droughts, wildfires, hurricanes)
Consumer and Business confidence
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