http://www.computerworld.com/article/3170899/it-industry/6-senators-say-us-firms-are-hiding-their-offshoring.html
Many U.S. tech companies don't report U.S. headcounts, but those that do may fit the model described by Beatty and Liao in their research paper.
Microsoft, for instance, discloses its U.S. headcount in its annual reports and increased its domestic workforce last year. In 2015, the company reported 118,000 full-time employees globally, 60,000 of them employed in the U.S., and 58,000 internationally. In 2016, Microsoft's overall workforce declined to 114,000, but its U.S. workforce increased to 63,000, and its international workforce declined to 51,000.
But another company, IBM, stopped providing its U.S. headcount in 2010. It's U.S. workforce had been declining as its overseas workforce increased. It now only provides a global headcount in its annual reports.