The advice from ISS is a setback for Greenlight and its manager David Einhorn. They have said GM shares are undervalued and would be more attractive if the company divided its common stock into shares that pay a dividend and shares that would reflect the automaker's growth potential.

Greenlight also has proposed a slate of three candidates for GM's board of directors.

On Friday, advisory firm Glass Lewis also advised against Greenlight's nominees for the automaker's board and its share split plan.

(Reporting By Joe White; Editing by W Simon)

By Joseph White