Pfizer terminated it's $160 billion agreement to aquire Botox marker Allergan.

It's something of a victory for lawmakers looking to stop corporate mergers designed to reduce taxes in the US. It would have cut Pfizer's tax bill by 'relocating' the company to Ireland where Allergan is registered.

In backing out of the deal Phiser will have to pay Allergan up to $400 million for it's expenses according to the merger aggrement. (Who negotiated that?)

The Treasury Dept. also implement a new rule that does not allow stock accumulated through a foreign company's U.S. deals in the last 3 years to count towards the "book value" needed to meet this new inversion threshold.