Apple, Adobe, Google and Intel agreed to pay $415 million (374 M€) settlement in a class action lawsuit where 64.000 employees accused them of making secret arrangements not to steal each other’s employees by offering better salaries, i.e. agreements to cap salaries.
▻http://www.reuters.com/article/2015/09/03/us-apple-google-ruling-idUSKCN0R30D120150903
The case was based largely on emails in which Apple co-founder Steve Jobs, former Google Chief Executive Officer Eric Schmidt and some of their rivals detailed plans to avoid poaching each other’s prized engineers.
More info about the initial settlement,
▻http://www.reuters.com/article/2014/04/25/us-apple-google-lawsuit-exclusive-idUSBREA3N28Z20140425
which was overruled later on:
▻http://www.nytimes.com/2014/08/09/technology/settlement-rejected-in-silicon-valley-hiring-case.html?_r=0