The Perrigo tax case was a dispute between Perrigo Company plc and Ireland’s Revenue Commissioners over a €1.64 billion assessment issued in November 2018, arising from the tax treatment of proceeds from the 2013 sale of the Tysabri multiple sclerosis drug rights. Revenue said the sale should have been taxed as a capital gain at 33%; Perrigo said it was trading income taxable at 12.5%. After a High Court loss on procedural grounds in 2020, Perrigo settled with Revenue on September 29, 2021 for €297 million, with a net cash payment of €266.1 million and no interest or penalties.
What Triggered the Assessment
In early 2013, Elan Corporation, an Irish pharmaceutical company, sold its global Tysabri rights to Biogen for $3.25 billion upfront plus ongoing royalties. Biogen agreed to pay 12% of global net Tysabri sales for the first twelve months, then 18% on annual sales up to $2 billion and 25% on sales above that threshold.
Later in 2013, Perrigo Company completed its acquisition of Elan in a cash and stock deal worth roughly $8.6 billion, with the combined entity incorporated in Ireland as Perrigo Company plc. Because the Tysabri sale closed shortly before that acquisition was finalized, the tax reporting for the proceeds fell to the new parent. Elan had treated the Tysabri intellectual property as trading stock and reported the sale proceeds as trading income. That single classification decision drove everything that followed.
Why the 12.5% Versus 33% Question Mattered
Irish corporation tax draws a sharp line between active trading income and capital gains. Trading income earned through regular business operations is taxed at 12.5%. Non-trading income from passive sources is taxed at 25%. Capital gains on asset disposals are taxed at 33%.
On a multi-billion dollar transaction, the gap between 12.5% and 33% is enormous. Trading treatment would tax the Tysabri proceeds at the lower rate. Capital treatment would nearly triple the bill.
Whether a transaction counts as trading in Ireland depends on the badges of trade, principles that originated in a 1954 UK Royal Commission report and have been adopted into Irish tax practice. They look at factors like the nature of the asset, how long it was held, the seller’s motive, and whether similar transactions occurred regularly. A company that routinely develops and sells intellectual property has a stronger case for trading treatment than one making a one-off disposal of a long-held investment. Elan’s position was that developing and selling IP was part of its ordinary pharmaceutical business, and that Revenue had accepted trading treatment on similar disposals in the past without objection.
The €1.64 Billion Assessment
In November 2018, the Irish Revenue Commissioners issued a Notice of Amended Assessment increasing Perrigo’s corporation tax liability for 2013 by approximately €1.64 billion, not including interest or penalties. Revenue’s position was that the Tysabri sale was a capital disposal rather than trading activity, and therefore taxable at 33% rather than 12.5%.
The reasoning focused on the nature of the asset. Revenue viewed the Tysabri IP as a capital investment rather than trading stock. A one-time payment of that magnitude from Biogen looked, in Revenue’s view, more like the divestment of a long-held asset than an ordinary sale in the course of trade.
The size of the retrospective reclassification stunned Perrigo and the broader international business community, and it raised questions about the predictability of a tax regime that multinationals had treated as stable. Perrigo’s share price fell on the news.
Perrigo’s High Court Challenge
Perrigo fought on two fronts. It launched a judicial review in the High Court arguing that Revenue should never have been permitted to issue the assessment at all, and it filed a separate appeal before the Tax Appeals Commission challenging the classification on its merits.
The judicial review, decided in November 2020, was about procedural fairness, not the tax question itself. Perrigo argued three grounds: that Revenue had breached the company’s legitimate expectations, that the assessment was so unfair it amounted to an abuse of power, and that it was an unjust attack on constitutionally protected property rights.
The legitimate expectation argument rested on three specific things: a Shannon Certificate issued by the Minister for Finance in 2002 that let Elan avail of a special 10% rate for approved trading activities in the Shannon Airport area; Revenue’s own Tax Briefing 57 from October 2004, which stated that trading activities meeting certain requirements would qualify for the 12.5% rate; and the course of dealings between 1997 and 2005, during which Elan reported IP disposals as trading income in financial statements clearly showing IP as trading stock, with no objection from Revenue.
The High Court rejected all three arguments. The judge found that none of the representations, individually or combined, amounted to a promise that Revenue would never issue an amended assessment. The court held that Perrigo “failed to establish that there is anything in the course of dealing between the parties which would make it unfair in the present case for the Revenue to exercise its statutory powers.” With no basis for legitimate expectation, the abuse of power and constitutional claims fell with it.
The ruling was narrow. The court did not quash the €1.64 billion assessment, but it also did not decide whether the Tysabri proceeds were trading income or a capital gain. That question was left to the Tax Appeals Commission, where Perrigo’s separate challenge was still pending.
The €297 Million Settlement
Rather than continue on both tracks, Perrigo settled with Revenue on September 29, 2021. The key terms:
- €297 million as a full and final settlement of all liabilities arising from the Tysabri patent sale, covering tax periods from 2013 through 2021.
- A net cash payment of €266.1 million after Revenue credited Perrigo for taxes already paid and unused R&D tax credits.
- No interest and no penalties.
- An alternative basis of taxation agreed on a without-prejudice footing, different from both Revenue’s position in the assessment and Elan’s original returns. Neither side conceded its legal position.
- Finality: Revenue agreed to take no further action regarding the assessment or any Tysabri-related income or transactions.
The settlement turned a potential €1.64 billion liability into a €266.1 million cash outlay. Perrigo described the outcome as a milestone that significantly reduced uncertainty.
What the Case Settled, and What It Didn’t
Because the settlement was structured on a without-prejudice basis, no legal precedent was set on the core question of whether large-scale IP disposals by pharmaceutical companies constitute trading or capital transactions under Irish law. Revenue retains the ability to challenge similar transactions in future, and companies cannot point to Perrigo as authority that IP sales qualify as trading income.
What the case did establish, in practical terms, is that Revenue is willing to pursue very large retrospective assessments when it believes income has been misclassified, and that the Irish courts will not readily block those assessments on procedural fairness grounds. Historical treatment of a transaction type, and Revenue’s silence on prior returns, did not amount to a binding assurance that the position was accepted. Companies making significant IP transactions in Ireland now have a strong incentive to seek advance opinions from Revenue rather than rely on past practice.