Gretl is an application software package for econometric modeling.
Capabilities of
Estimation of parameters using the method of least squares (OLS), method of maximum likelihood (ML), generalized method of moments (GMM), etc;
Seasonality extraction using X-12-ARIMA and TRAMO/SEATS (Time series Regression with ARIMA noise, Missing values and Outliers / Signal Extraction in ARIMA Time Series) embedded packages;
Time series models: autoregressive moving average (ARMA), autoregressive integrated moving average (ARIMA), generalized autoregressive conditional heteroscedasticity (GARCH), vector autoregressive (VAR), vector error correction model (VECM), etc;