Before revision:  We propose an adaptive recursive estimation routine for GARCH models using the technique of Variance Targeting Estimation (VTE) to alleviate the convergence difficulties encountered in the usual QML estimation .
After revision:  We propose an adaptive recursive estimation routine for GARCH models using the technique of Variance Targeting Estimation (VTE) . This recursive method has computationally efficient properties, while VTE alleviates some convergence difficulties encountered in the usual QML estimation .