The deal is the third eye-catching one of the week in Europe, allowing the sector to end the year with a flurry after being overshadowed this year by a frenzy of merger and acquisition activity in the U.S..

However, much of the recent activity has been quite different from what’s been happening in the U.S., where many deals have focused (almost exclusively in some cases) on cutting the corporate tax bill by moving the company headquarters outside the U.S..

Europe already offers extensive tax breaks to pharma companies through arrangements such as ‘patent boxes’ that cut taxes on innovation. So the deals that have taken place have been more about sharpening companies’ focus and looking for capital-light ways to boost drug pipelines.

GSK’s deal falls into both categories: HIV treatments are already one of its biggest revenue generators, and buying the BMS portfolio (through its majority-owned unit ViiV) will cement its place as the second-biggest player in the segment behind Gilead Sciences (GILD).

But by the same token, much of the purchase price will be deferred until the drugs under development have hit key milestones. If they do that, the deal could be worth up to $1.5 billion for Bristol, but GSK is only paying $350 million up front.

The deal comes a day after AstraZeneca plc (AZN) said it’s spending $4 billion on a 55% stake in leukemia specialist Acerta. AstraZeneca was also part of a big deal with France’s Sanofi SA (SNYNF) in November that gave each company access to over 200,000 patents from their respective intellectual property libraries, with the aim of bringing down the cost of researching new drugs.

Sanofi in particular has been wary of any big strategic moves since its high-profile firing of CEO Chris Viehbacher a year ago. But it made its biggest deal of the post-Viehbacher era earlier this week when it swapped some $25 billion worth of assets with Germany’s Boehringer Ingelheim AG. That deal will make Sanofi the world’s biggest consumer healthcare specialist, while making the German company a global force in the animal health business.