[asuffield]

Here's an (old) discussion of some of the major points in understanding that question: http://www.forbes.com/sites/timworstall/2012/11/01/so-how-mu...

I haven't seen an explanation of where that 0.005% number comes from, but I would be unsurprised to find similar forms of confusion in it.

[jsnell]

The EC's press release is pretty clear on where the number comes from, and I do not see any such forms of confusion there: http://europa.eu/rapid/press-release_IP-16-2923_en.htm

[asuffield]

Ah, I see. So what they're saying in this case is that 0.005% is the fraction of Apple's global non-US profits that was paid as tax in Ireland.

That's not the same thing as saying it was "a 0.005% tax rate". The issue is over what fraction of the non-US profits are taxable in Ireland, not over the tax rate.