GEM prospects and GEM members are experience rated. Each entity is rated based upon an actuarial model developed collaboratively for GEM by Milliman (actuarial consulting firm), and GEM's underwriting manager. Underwriting is performed "in house" using the specialized expertise of GEM's staff members. GEM offers transparency in its rating methodology allowing members to fully understand how their premiums are calculated.

Joel Kress, Underwriting Manager, has primary responsibility for coordinating the underwriting review performed by GEM. Pool information that is part of the GEM underwriting evaluation includes: historical loss experience, most recent claims audit, actuarial studies, underwriting process, primary policy form, state tort statutes, scope/quality of primary control services, and audited financial audit statements.