Governmental employers in the US (that is, federal, state, county, and city governments) are currently barred from offering 401(k) plans unless they were established before May 1986.
To help ensure that companies extend their 401(k) plans to low-paid employees, an IRS rule limits the maximum deferral by the company's highly compensated employees (HCEs) based on the average deferral by the company's non-highly compensated employees (NHCEs).