Worldwide levels of M&A have reached an all-time high, breaking the previous record set before the crisis, according to Thomson Reuters data. The tie-up between pharmaceutical companies Pfizer (PFE.N) and Allergan (AGN.N) — 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.