As one of the participants already mentioned, it all depends on the strategy behind M&A and the financial strength of both companies. In certain circumstances, like adding a new capability / expertise to the acquirer by acquiring another company, instead of developing this capability / expertise in-house, can result in no head-count changes in the company acquired. It also very much depends on the industry – in certain industries with in-demand skillsets one ultimately buys talent, so cutting staff is counter-productive. Sometimes efficiencies can be achieved by organising better and improving Revenues on existing staff without the cuts as well as improving other ‘go to market’ strategies. Unfortunately, cost cutting is the quickest way to demonstrate ‘success’ of the acquisition and is a default setting in many cases, although in my experience this was not a path chosen.