Pfizer's plan to acquire Allergen is criticized as an inversion transaction that would transfer the giant drug company's headquarters and taxable profits to Ireland, but a Reuters' examination found that the firm has already been shifting profits to County Court for more than ten years.

Pfizer's move to buy Allergen has received political backlash for allegedly being a move to evade tax in the US, but according to an examination by Reuters on the drug makers corporate filings in Europe and other data, the company's profit from scientists in America and patients overseas are being shifted to its subsidiary located in the rolling hills of County Cork.

Pfizer has done moves in the past that financial experts consider as "tax inversions" or "tax dodging." The New York Times reported that the drug maker has $140 billion overseas and its move to take over Allergen could shift its headquarters from New York to Dublin. Labor union advocacy organization Americans for Tax Fairness recently accused Pfizer of strategizing a global "tax dodging" pattern. Presidential candidates, the Congress, and even the Treasury Department condemn these inversions and are looking for ways to come up with laws that would discourage these moves.

In the report by Americans for Tax Fairness, Pfizer executives aren't really subtle about their attempts to significantly decrease their US tax bills. One of the company's head believes that the drug makers' effective tax rate was 25.5 percent in 2014, but could be radically cut if Pfizer's legal address is transferred to Ireland through the takeover of Allergen.

The United States' tax rate is 35 to 40 percent, which is colossal compared to Ireland's 12. 5 percent tax rates. President Barack Obama considers inversions as unpatriotic and made some changes in the tax laws last year to make inversions more difficult. Allergen fears that the acquisition deal would have additional deals from the US treasury department.