We develop a new test for threshold-type regime changes in the risk exposures in portfolios with a large number of financial assets whose returns exhibit an approximate factor structure. Unlike existing procedures to detect discrete shifts in factor models, our test is robust to regime-specific...

We propose a methodology that can efficiently measure the Value-at-Risk (VaR) of large portfolios with time-varying volatilities and correlations by bringing together the established historical simulation framework and recent contributions to the Dynamic Factor Models literature. We find that...