The publication of the FOMC policy statement triggers an immediate and dramatic spike in stock market volatility.

When the clock strikes 2:00 PM in Washington, the Federal Reserve releases its policy statement. Instantly, algorithms and traders digest the text. This triggers a massive, sudden spike in the standard deviation of stock returns. Prices swing wildly as the market struggles to price in the new interest rate reality. This initial burst of trading activity happens in a matter of milliseconds, showing how quickly modern financial systems react to official policy updates.