General contractor
A general contractor, usually called a GC, is the company that holds the prime contract on a construction project and hires subcontractors to perform specific trades. GCs typically require subcontractors to pass a prequalification process before being allowed to bid, and your workers' comp EMR (experience modification rate) is one of the fastest items in that package for a GC to check, since it's a single number that either clears their threshold or doesn't. The threshold a GC sets isn't standardized. Some cluster around a mod below 1.0; others use a different number, and some will still consider a sub above their stated line if the rest of the package is strong. There's no way to know which kind of GC you're dealing with except by asking, or by finding out you've already been screened out. On public and institutional work, the GC is often working from a threshold the owner set rather than one they chose themselves, which is part of why the number can be firmer on those jobs than on private work.
See also
Is your mod right?
Most contractors have never had the worksheet compared to the loss runs and payroll behind it. See what your mod is costing you, or get on the list for a full verification.