Recently, I’ve been thinking about a question: why do currency prices sometimes surge after the same economic data releases, and other times fall? Actually, there’s a systematic logic behind this.

To truly understand the fluctuations in the foreign exchange market, you must clarify what factors influence forex. I’ve summarized the 9 most critical factors, which operate in the short, medium, and long term.

Let’s start with the short term. Interest rate changes are the most direct catalysts. When a central bank announces a rate hike, investors immediately react, because higher interest rates mean higher deposit returns, increasing demand for that currency, and causing the exchange rate to strengthen. The Reserve Bank of India, for example, stabilized the rupee by raising interest rates that year. Market sentiment also cannot be ignored; it’s a very subtle factor—once someone starts bullish on a currency, other investors will follow suit, creating a self-reinforcing cycle. During the housing boom in the U.S. in 2005, this was exactly how it worked: low interest rates triggered expectations of rising home prices, which in turn boosted the dollar.

In the medium term, political stability is a key influence on forex. Think about Brexit—on the day of the referendum, the pound plummeted. Investors tend to prefer buying currencies from politically stable countries because a stable government can foster economic growth. Inflation rate is also very important; nobody wants to hold a currency that keeps depreciating. Zimbabwe’s example is the most extreme—hyperinflation caused the currency to become completely unattractive. Employment data reflects economic vitality; high unemployment indicates economic stagnation, and the U.S. dollar index tends to rise when non-farm payrolls are strong. Government debt acts like a country’s credit rating; countries with mountain-high debt find it hard to attract foreign investment. One reason the rupee weakened is India’s high government debt. The performance of capital markets is also a barometer—long-term stock market declines indicate investor confidence is lacking, and the corresponding currency will weaken.

In the long term, trade terms and fiscal policies are decisive factors. China’s attractiveness to forex traders is largely due to its significant trade surplus, with exports far exceeding imports. After 2005, as China’s capital markets soared, the USD/CNY experienced a long-term appreciation. But after 2022, with economic growth slowing, this trend reversed. A country’s currency and fiscal policies determine its attractiveness to foreign capital; if government policies are friendly, investors will naturally flock in, boosting demand for that currency.

Understanding the logic behind these 9 factors influencing forex enables better prediction of exchange rate trends. The forex market may seem complex, but in fact, everything can be traced and understood.