Teva has raised its stake in Mylan to 4.61%, which will allow it to take its acquisition bid to court “should it become necessary”.

Mylan reincorporated in the Netherlands last year, and under Dutch law owning this amount of shares allows Teva to legally challenge the company’s continued rejections of its $40 billion takeover offer.

In a letter last month, Mylan claimed that Teva purchasing these shares violates US antitrust laws, but Teva has countered by saying that such laws should not matter for a company who has moved its domicile abroad.

"We note that you have been saying you are a Dutch company when you believe it helps you create unprecedented governance structures, a UK company when it helps you lower your US taxes and a US company when you believe it helps you prevent Teva from purchasing Mylan shares," CEO Erez Vigodman and chairman Yitzhak Peterburg say.

Merger triangle

Mylan itself is in the process of attempting to buy Perrigo, but has also been rejected multiple times.

The company has accused Teva of using its bid to try and distract from this purchase. In May Mylan implored the Israeli firm to make its intentions clearer before a planned special general meeting where shareholders will vote on whether to endorse the Perrigo offer.

Teva has now said that it will limit its shares in Mylan to less than 5% if this meeting is held before September.