Symantec announced the news of entering into a definitive agreement to acquire Blue Coat for $4.65B on June 12, 2016. The deal is expected to close by Q3 2016 subject to approval by regulatory bodies.
In Enterprise Security space, a large portion of the exit activity has taken place through M&As, with 131 acquisitions during last 5 years of the total 159. IoT Security & Industrial Security are upcoming sectors.
More at http://blog.tracxn.com/2015/12/30/tracxn-report-enterprise-security/