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 . Finally, empirical results demonstrate a favorable trade-off between  the ability to adapt to time-varying estimates and stability of the estimation routine .
After 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 due to a lack of convexity. Empirical results demonstrate a favorable trade-off between the ability to adapt to time-varying estimates and stability of the estimation routine .