It appears at least a section of the Trump administration is working on reducing the effectiveness of H1B visa program. The target here is American Competitiveness in the 21st Century Act (AC21), which was passed with bipartisan support in 1998.
Sections of the act allows H1B works to continue working in United States, while they are waiting for a Green Card. Currently it takes 12-15 year for Indian immigrant to obtain Green Card, i.e. after they have qualified and have a approved petition. This is primarily due to annual limits set per country. Countries like Pakistan and Srilanka enjoy quicker turnaround (less than 6 months) as there is not qualified candidates from these countries and per country limit is not based on the population of the original country.
Current Law & Tweaks
As H1B in its original form allowed candidates upto a maximum of 6 years, AC21 allowed candidates who have approved I140 (Permanent resident), but awaiting country quota. While a legislation is needed to change this condition, Trump administration doesn’t have enough votes. Hence tweaking of the wording of the document is being considered. Eitherway the end result might be mass deportation of nearly half a million well paid H1B candidates.
While most of them might continue to perform the same job from their home country, this will impact local property values, property taxes, Social security taxes etc. At an average these individuals and families contribute to the local economy and will set a path where companies might move their offices to countries with less restriction.