The tie-up between pharmaceutical companies Pfizer (>> Pfizer Inc.) and Allergan (>> Allergan, Inc.) -- the second biggest merger ever -- has pushed deal levels to $4.2 trillion, surpassing the $4.1 trillion seen in 2007.

There has been a frenzy of dealmaking this year as confident management teams sitting on large cash piles and hunting for growth seek out opportunities, after several fallow years following the global financial crisis.

Pfizer, the producer of Viagra, said on Monday it would buy Botox maker Allergan in a deal worth $160 billion.

It comes less than a fortnight after AB InBev (>> ANHEUSER-BUSCH INBEV), the world's biggest beer brewer, launched its offer for SABMiller (>> SABMiller plc) in a deal worth about $106 billion.

If those transactions close, that will make Pfizer's move the second deal this year to cross the $100 billion mark -- a milestone previously hit by only four mergers.

Pfizer is a regular contributor to M&A activity: six of the top 20 biggest pharmaceutical deals involved the company, according to the data. Its latest deal boosts global healthcare merger activity to $649.4 billion - more than the previous two full years combined.

The biggest ever deal was Vodafone Airtouch's 1999 acquisition of Mannesmann for $202.8 billion.

(Reporting By Freya Berry, editing by David Evans)