This is largely dependent on organization size, market size and reach. A small merger can consist of an organization of fewer than 500 employees or an organization with a single market focus. The risks are the same in my opinion, whether small or large. Cultural integration will be an issue no matter what size the merger is. I do think that with a large mega-merger the risks are exponential and thus it becomes more critical to achieving the integration goals within the specified time frame of the business case. Thus, it is more a question of the size of the risk, not that there are different risks.