""In the 2015 fiscal year, for instance, the top 10 firms received 38% of all the H-1B visas in computer occupations alone. All these firms, except for Amazon and to a partial extent IBM, are outsourcers."
Maybe this is technically correct, but this statement is misleading.
In 2015, the top-8 firms received 49,539 H1-B visas or over 58% of the 85,000 nominal allotment. Of these, about 700 had advanced US degrees. All 8 were Indian outsourcing companies, and the overwhelming majority of the visa approvals went to Indian nationals, about 48,650 Indians from these top-8 firms.
Of course, the ironic thing was that a few years ago, my company was unable to obtain an H1-B visa for our new Indian worker who has an EE PhD from a top-5 US engineering school and is definitely top-notch. He was forced to apply for an outstanding researcher visa instead. Ironically, the low-paid, not outstanding Indians displaced the highly paid, very outstanding Indian.