Maybe it's because of coming from a European background, but this kind of questions are quite baffling for me. I know you mean well, but I find that the idea that corporations do this kind of thing doesn't need any more proof than the fact that the earth is round.

If one follows the news, there are constant reminders of this kind of lobbying going on (corporations asking for special treatment, especially when it comes to taxes) for a whole century. Besides a lot of this is done right out in the open. I mean coorporate lobbying was invented exactly for that -- to push governments for favorable laws, special treatment, laxer environmental and other protections, etc. On top of that, there are all kinds of under-the-table deals (with lots of them exposed frequently) with politicians and corporations.

That said, here are some pointers to the issue. First the general Wikipedia article:

A number of published studies showed lobbying expenditures can yield great financial returns. For example, a study of the 50 firms that spent the most on lobbying relative to their assets compared their financial performance against that of the S&P 500 in the stock market concluded that spending on lobbying was a "spectacular investment" yielding "blistering" returns comparable to a high-flying hedge fund, even despite the financial downturn of the past few years. A 2011 meta-analysis of previous research findings found a positive correlation between corporate political activity and firm performance. Finally, a 2009 study found that lobbying brought a substantial return on investment, as much as 22,000% in some cases. https://en.wikipedia.org/wiki/Lobbying#United_States

And the US specific one: https://en.wikipedia.org/wiki/Lobbying_in_the_United_States

The Atlantic: http://www.theatlantic.com/business/archive/2015/04/how-corp...

The Guardian: http://www.theguardian.com/politics/2014/mar/12/lobbying-10-...

National Review: http://www.nationalreview.com/article/421664/corporate-lobby...

Fortune: http://fortune.com/2015/09/04/lobbying-corporate-washington/

Economist: http://www.economist.com/node/21553020

Forbes: http://www.forbes.com/sites/chrisbarth/2011/12/14/29-compani...

Oxford University Press: http://www.amazon.com/The-Business-America-Lobbying-Corporat...

Lawrence Lessig: http://www.amazon.com/Republic-Lost-Money-Corrupts-Congress/...

The Influence Machine: The Influence Machine: The U.S. Chamber of Commerce and the Corporate Capture of American Life

Lobbying America: http://www.amazon.com/Lobbying-America-Politics-Business-Twe...

And those are "establishment" sources -- you'd get far better coverage in more outspoken and critical voices.

Regarding Apple in particular: http://www.theguardian.com/business/2015/jan/21/us-tech-tax-...

http://www.theguardian.com/technology/2014/sep/30/apple-repa...