Two reasons: they’re not always actually intra company. Apple and Apple Ireland are different companies - and while intuitively it feels like you can just lump them together, it’s often much more complicated than that.

Second, because it is actually moving money. If I’m a Canadian software company that does most of its sales in the US through an American subsidiary (not uncommon), the way it works is the American subsidiary pays the Canadian company back for the sales of the Canadian company’s IP. Otherwise the money would never get back to Canada and the developers wouldn’t get paid! Furthermore, would be silly and tax-suboptimal to ignore the IP-money-flow and treat the Canadian company as nearly pure loss while treating the American one as nearly pure profit.

One is a wholly owned subsidiaries of the other. It's not of course a sufficient condition, but I m sure it's possible to distinguish the relationship between Apple and Apple Ireland from that between say Dell and EMC, or IBM and Red Hat, or the daughter companies of conglomerates like Berkshire Hathaway.

> Otherwise the money would never get back to Canada and I wouldn’t be able to pay my developers!

It doesn't have to be paid for the right to sell the IP. You can just move all revenue back into headquarters' coffers, and use it to finance the various cost centers. Just write the law so that it cannot be called a sale.

> You can just move all revenue back into headquarters' coffers

So it's actually moving money! And you need a reason to move money from one company (in the US) to another (in Canada). Call it sale, call it IP licensing...

The difference is that "IP" production occurs where the R&D departments exist and salaries have to be paid, rather than where the corporate taxes are lowest.

The difference with what?

The context was "If I’m a Canadian software company that does most of its sales in the US through an American subsidiary (not uncommon), the way it works is the American subsidiary pays the Canadian company back for the sales of the Canadian company’s IP."

The IP production occurs in Canada where the R&D departments exist and salaries have to be paid and the US subsidiary company pays to the Canadian parent company.

They cannot just "move all revenue back into headquarters' coffers."

The difference between moving money in your situation and in Apple's, where there's no correspondence between where engineers are located and where IP is licensed from.

By forcing all revenue to go through a single point (the headquarters) it's much harder to establish fake licensing like Apple Ireland's.

Ok, I was commenting on the US subsidiary of Canadian firm example (which you didn't seem to agree on).

But I don't think that the meaning of "forcing all revenue to go through a single point" is clear at all.

From the point of view of most countries sending money out to Cupertino wouldn't be an improvement over sending it to Cork if that still means that they don't get to tax it.