Allergan, Pfizer call off proposed $160B merger

[...] the two drugmakers will focus on other strategies to boost profits and sales quickly, with Pfizer saying it will decide by year's end whether to separate its global established products business, which sells older, mostly off-patent drugs.

The companies' decision could deter other tax inversions in the works — exactly the impact the Obama administration is seeking by having Treasury issue 300-plus pages of new regulations that remove or reduce key financial benefits of a tax inversion.

With Pfizer's planned inversion looking like the start of a dreaded trend, tax inversions became a hot issue in the presidential race, with some candidates calling companies considering such deals "unpatriotic."

[...] on the heels of the new Treasury rules, President Obama held a news conference Tuesday afternoon, saying the rules are meant to prevent "one of the most insidious tax loopholes out there" and make wealthy corporations shoulder their tax responsibility like working class Americans.

Pfizer has a history in this century of doing mega-acquisitions that allow it to cut costs and increase sales to boost profits quickly.