For testing error variance instability, a test based on CUSUM squares of the residuals in HAR model is constructed and its limiting null distribution is derived to be a simple function of the standard Brownian bridge. A finite sample Monte-Carlo experiment shows reasonable size and power...

A CUSUM test is proposed for testing structural breaks in a long-memory heterogeneous autoregressive model. The limiting distribution of the CUSUM test is shown to be a simple function of a standard Brownian bridge, contrasting with the nuisance parameter dependent asymptotics of other CUSUM...