You don't declare profits. You just invoice or lend between international elements of your group with timing such that at the end of year/quarter/reporting period in each jurisdiction you've lost money or made none.
A lot of money vanishes this way, a lot of money is invented this way.
Ahh. That's smart. I guess that's related to the other strategy I've heard of national HQs charging each other made-up sums in 'branding fees' to use the company logo.
Part of the EU rules is that it is a single market. However the Irish deal treats it as individual markets from the point of view of the Irish government and soobpy collects taxes on the Irish generated part.
Like Apple google negotiated a deal that only Ireland profits are taxed in Ireland but European profits are declared there but are untaxed.
The UK could reduce it's tax rate to 1% and they'd still have their Irish tax structure as that gives them 0% across all of Europe.
It's hard to go lower than 0.