Interest Rate Curve Calibration with

Monte Carlo Simulation

Problem raised by Indizen Technologies S.L.

Coordinating teachers of the problem:

Gerardo Oleaga (Universidad Complutense de Madrid)

Jorge Valdehita Prieto (Indizen Technologies S.L.)

 

Exposition of the problem:

The value of an interest rate curve at a future time can be known today and can help us to obtain today's values for fixed income securities, futures, derivatives, etc. However, if we move forward in time and wish to know the value of those securities in the future, then the interest rate curves ought to be simulated.

A Monte Carlo simulation of a stochastic process is a procedure for sampling random outcomes for that process. Interest rate curves can therefore be simulated once a specific evolution model for the curve has been assumed. A calibration method for the interest rate curves is then needed so that the curves look similar to the ones in the market.

 

Every point on the given interest rate curve is a different Risk Factor to be simulated. To simplify the problem, let's consider for each Risk Factor a Log-Normal Geometric Brownian Motion as follows:

 

 

Given historical series for each Risk Factor from the interest rate curve, some statistical measures such as  and  ought to be calculated in order to simulate different scenarios.

 

Curve Calibration for the interest rate curves is the next step to be considered in order to obtain curves that show what truly happens in the market. For instance, a simple simulation will consider short and long term interest rate structures as equal.

The Nelson-Siegel Model is a parametric estimation technique for yield curves. It is a non-polynomial model to prevent abrupt changes in the term structure of interest rates, mostly for the long term.

 

 

, where ,  and  indicate the contribution of long, short and medium term components respectively;  is the decay factor and m is the time to maturity.

 

Scheme of the work to be done:

 

1) Do a simple MonteCarloSimulator in Matlab to produce interest rate curve scenarios with a Log-Normal evolution model for each TimeStep.

 

2) Write a Matlab function named NelsonSiegelCalibration to perform the calibration method for the interest rate curves. Calibrate the corresponding Risk Factors from the curve with the given historical series. A historical series for the parameters  is then produced. Now, use the MonteCarloSimulator to produce different interest rate calibrated curves for each TimeStep assuming that the parameters have a Log-Normal evolution model. Compare the results to the ones obtained from the usual simulation.

 

3) Conclusions and Consequences. Does the calibration produce interest rate curves similar to the ones in the market? Is it reasonable that the parameters have the same evolution model as the curve? If not, can you tell how the parameters are distributed? Can you think of other ways to produce a calibration for interest rate simulated curves?