It definitely varies a ton. I've observed more that H1B's keep employee mobility lower, so employees on H1Bs tended to be paid less due to the natural bumps th

It definitely varies a ton. I've observed more that H1B's keep employee mobility lower, so employees on H1Bs tended to be paid less due to the natural bumps that come out of switching jobs every few years, especially going from an associate to senior/staff level where often the company throws a small raise with promotions that don't keep up with market rates. One other factor that I experienced is when I was in senior leadership we absolutely tracked 'flight risk' that factored in to retention programs for top talent, and H1Bs were by the nature of it viewed as lower flight risks so less likely to fall into these programs.