Hi listers, greetings from Paris ! Well, I checked on my system and The loop runs ok with the ols command but not with the system commands. however, will the loop runs, gretl tells me there is a near singularity in my data. I try to check the script by calling a simpler system, with the strict minimal input : the prices and income. I will then attempt to increase complexity to check the behavior of GRETL. Note also that I spotted some problems with the data, serious enough to cause to regress on singular matrices (duplicated or zero columns) for some of the loop index values. I fixed that but the problem persists. I check to see if it is the system command that pose problems. I tell you back when i have anything new thanx & regards cheers Franck -- Franck Nadaud CIRED UMR 8568 CNRS - EHESS, ENPC, ENGREF, CIRAD 45 bis avenue de la Belle Gabrielle 94736 Nogent-sur-Marne Cedex TEL: 33-1-43-94-73-94 FAX: 33-1-43-94-73-70 MOB: 06-07-39-92-75 France