The costs associated with the following five problems are caused or increased by poor M&A management:

Bailing out by managers and executives is one of the first signals that a merger is being mismanaged.
Typically, some of the best talent is the first to go. And their leaving more than likely means that somebody in the top ranks of the company made a mistake. There was something someone did, or didn’t do, that helped produce the bailouts.
Parent company executives have to move fast and do the right things to keep the people who count. Too often, though, just the opposite happens. The acquiring firm drags its feet and does things clumsily ...