Interest rate risk is a fundamental concept in financial economics and risk management that investigates the potential for adverse changes in market interest rates to negatively impact the value of assets, liabilities, and off-balance sheet instruments, or affect an entity's net interest income. It characterizes the sensitivity of financial positions to fluctuations in interest rate levels, yield curve shapes, and volatility, representing a critical area of study for financial institutions, corporations, and investors seeking to understand and mitigate the financial consequences of interest rate movements.