Do H-1B Employers Underpay Their H-1B Employees?
Research by the Cato Institute says no.

100% of H-1B Employers Offer Average Market Wages—78% Offer More
The H-1B program is the main on‐ramp that recent foreign college graduates have to the U.S. labor market. Excluding these new skilled foreign workers, the entire immigration system for skilled foreign labor would shrink by more than 50 percent, and America would lose talented workers that are essen…