Global life sciences M&A deal values hit $131.8 billion in 2013 in 203 transactions with disclosed deal values greater than or equal to $20 million. That compares to $108 billion in total deal values for 211 transactions in 2012. Although 2013 total deal values were 21.3 percent higher than in 2012, the number of deals was down by 3.8 percent.

M&A transactions in which the target company was based in the United States, accounted for 108 deals in 2013 compared to 130 deals in 2012, a drop of 16.9 percent. However, total deal values for these companies were up 8 percent year over year.

Except for AstraZeneca, Big Pharma stayed away from acquisitions in 2013, preferring to continue externalizing its R&D by opening up innovation centers and increasing early-stage partnering activity with biotech companies and academic institutions. The big pharmaceutical and big biotech companies accounted for just 13.3 percent of the transactions in 2013, but one third of the year’s total deal values.

Thermo Fisher Scientific’s $13.6 billion acquisition of Life Technologies was the biggest M&A deal of 2013. Amgen scored one of the biggest deals of the year with the $10.4 billion acquisition of Onyx Pharmaceuticals for its oncology pipeline. The rare disease specialist Shire was also in acquisition mode. It beefed up its portfolio with ViroPharma for $4.2 billion in November and acquired two VC-backed biotechs: Lotus Tissue Repair and SARcode Bioscience.

Two of the year’s biggest transactions were based in part on the tax advantages the buyer would enjoy by being domiciled in Ireland: Perrigo’s $9.2 billion takeover of Elan after the Irish biotech sold its prized Tysabri rights to Biogen Idec for $3.3 billion; and generic powerhouse Actavis’ $8.5 billion purchase of Warner Chilcott.

As biotech IPOs picked up steam, acquisitions of venture-backed biotechs slowed. Though these deals continued to be structured with the total payout milestone-based, backers of the companies that did get acquired saw more of the total potential payout upfront. Among the biggest M&A upfront payouts were Johnson & Johnson’s $650 million upfront payment for Aragon Pharmaceuticals with another $350 million tied to milestones. Aragon’s lead asset was in mid-stage development to treat hormone driven cancers. AstraZeneca paid $560 million upfront to acquire Pearl Therapeutics and its late-stage inhaled small molecule therapeutic to treat COPD. The biotech’s backers could get up to $590 million more based on the achievement of specified milestones.

In 2013, IPOs were all the rage. With their pace likely to slow in 2014, it will be interesting to see if there will be a pick up in venture-backed life sciences companies M&A.