← All projects

Statistical analysis

Understanding portfolio tail risk

Using a Vasicek one-factor model and Monte Carlo simulation to study how correlated defaults shape credit portfolio losses.

Duke · MATH 789 team project

PythonMonte CarloVasicek model

The question

How do default probabilities and dependence between borrowers change the distribution of credit portfolio losses?

The approach

  • Used the public Default of Credit Card Clients dataset as the portfolio basis.
  • Modeled defaults through a shared systematic factor and borrower-specific factors in the Vasicek framework.
  • Simulated loss distributions under alternative default-probability and correlation assumptions, comparing Value-at-Risk and Conditional Value-at-Risk.

What this explores

The simulations show why expected loss alone does not describe portfolio stress: changing default dependence can alter the tail of the loss distribution substantially.

Scope & limitations

Results depend on the one-factor model, selected scenario assumptions, and a historical dataset. They are a classroom simulation, not a forecast of current credit losses.

Team: Jordan Andrew, Ammy Lin, Farnoosh Memari, and Tonantzin Real Rojas. Completed for MATH 789 at Duke University.

Project summary and attribution are based on the repository documentation.