System GMM coefficient is above 1 or below -1.0

[TIFFANY ZHAO]

Hi all,
I am examining whether firm's performance can persist in the short run. I use a two-step System GMM.

After I run xtabond 2, a great many coefficients turn out to be above 1.0 or below -1.0. Is that possible? If not, what is the problem? Thanks.

[Dario Maimone Ansaldo Patti]

Maybe you could post the routine you used and the results you got. My first suspect is that there is a problem with the set of instruments you selected.