Several other pharma companies did the same tax trick as ALXN and ended up paying several billion $ tax penalties in UK and USA. The trick works by licensing your product to your manufacturing subsidiary in a tax haven. ALXN won't be able to get away with it.
Make sure to do some homework before spitting out errors. ALXN is a US company located in Cheshire, CT. You need to investigate the tax landscape ---start with Section 7874 of the IRS Code. If that is too much work there are reports from bulge bracket players that can lay it all out for you.
I am telling you once more; What ALXN is doing is tax avoidance, tax fraud? Read Adam Feuerstein's blog. He summarises it very good. ALXN acquired a vialling facility in Ireland. Meaning, it is the facility at which Soliris is put into small bottles and boxed. So you can imagine how much value is created there. Now they are going to claim that this facility is actually their new headquarters, where all executive decisions are made, and avoid paying several hundred million $ of tax in the USA. All executives actually reside in the USA, and the actual acting HQ is also in the USA. Now just because they say so, they expect IRS (taxman) to believe that the HQ is moved to Ireland. Big pharma tried this in 1990's. They claimed that their licences (patents) are owned by manufacturing facilities in tax havens such as Puerto Rico or Singapore. They ended up paying multi billion $£ tax penalties in the US and United Kingdom. Read history. What ALXN is doing is unethical, and unlawful. They (and investors) will pay dearly.