DRUGMAKER Perrigo is facing a potential legal action over not disclosing a €1.6bn Irish tax bill earlier.
The company told investors in early November that an issue had arisen with Revenue. It said that because it intended to dispute Revenue's position, the amount it could ultimately be asked to pay couldn't be quantified, though it could be "material".
Revenue then issued a demand for €1.6bn in late November, with Perrigo disclosing the size of the demand some three weeks later just before Christmas. Its stock plunged sharply after the size of the bill was revealed.
Block and Leviton, an American law firm, said it "continues to investigate whether Perrigo... and certain of its officers and directors violated federal securities laws".
It said the company had not disclosed "material details" when it first told investors the issue had arisen.
The law firm, which describes itself as a securities litigation firm, frequently carries out such investigations in an effort to win money for investor clients. Perrigo declined to comment on the potential case.
The Revenue demand stems from a transaction carried out by Irish drugs business Elan, which Perrigo later bought. Elan sold the intellectual property behind a drug called Tysabri. Revenue has since determined the proceeds should have been taxed at the 33pc rate of capital gains tax. But Perrigo contends that the proceeds of the sale were trading income and should have only been subject to 12.5pc corporation tax.
Perrigo, which has its headquarters in Dublin, is one of the world's biggest suppliers of over-the-counter medicines.