Women working full time in the United States have historically been paid just 80 percent of what their male counterparts are paid. This gap in pay tends to follow a woman from job to job because employers base a woman’s future salary on her previous, inequitable salary. Employers are blamed for perpetuating the gender pay gap and for capitalizing on cost savings in the pay disparity rather than closing the gap by paying men and women equally for the same position.

In an effort to combat this trend, many states and cities have passed salary history bans as part of broader legislative efforts to prevent employers from under-paying women. States like California, Oregon, Massachusetts and Delaware have already adopted salary history ban laws, and cities like San Francisco, San Diego, New Orleans, Pittsburgh, Albany, New York City and Philadelphia have also joined the cause. Even Puerto Rico has adopted salary ban legislation.  Some of these laws went into effect in 2017, while others will go into effect this year and into 2019.