Vasicek Model

The Vasicek model is a foundational mathematical model in finance that describes the evolution of interest rates as a mean-reverting stochastic process. It was one of the first models to introduce the concept that interest rates fluctuate around a long-term average, which is a key feature of realistic rate behavior.

The model assumes that the short rate follows a continuous-time process with constant parameters, making it highly tractable for analytical derivations. While it is praised for its simplicity and mean-reverting property, it has the limitation of not always fitting the current market yield curve perfectly.

This led to the development of more complex models like Hull-White. In the context of financial derivatives, the Vasicek model provides a baseline for understanding how interest rate volatility impacts the pricing of bonds and options.

It is widely taught as an introductory framework for grasping the mechanics of stochastic interest rate modeling. Its influence persists in both traditional finance and the design of modern DeFi interest rate protocols.