
Close Date: FebruaryPrice: $612 millionClosed right at the start of the year, this deal gives Dell a mature portfolio of managed service capabilities and a better way to engage with SMB and mid-market customers thirsting for turnkey security offerings.

Close Date: May Price: Undisclosed,A private equity firm with some serious security chops– already owning firms like Entrust, LANDesk NetIQ and SonicWall–Thoma Bravo continued its security spending spree in 2011 with a purchase of Tripwire, security and compliance automation solution with particular strengths in cloud security.

Close Date: Pending, Announced in DecemberPrice: $1.3 billionBefore the year was out, Thoma Bravo logged an even bigger buy when it picked up Blue Coat for a monster price tag. The deal was a win-win, giving ailing Blue Coat some stability after disappointing earnings and the ouster of a CEO after less than a year of service and adding content security to Thoma Bravo’s portfolio.

Close Date: JulyPrice: $390 millionAs organizations grapple with how to mesh complicated eDiscovery procedures with archiving and back-up, many will look to Symantec for the technological backbone to make it happen. The Clearwell acquisition gives the storage and security giant a key component to strengthen its eDiscovery chops.

Close Date: OctoberPrice: UndisclosedIBM was hoping to better tie together its security offerings with the streamlined sophistication of an in-house security information and event management (SIEM) platform. That’s where Q1 came into play, a company whose acquisition will give Big Blue customers an integrated source for analytics to spot those advanced persistent threats more quickly.

Close Date: DecemberPrice: UndisclosedInterestingly announced on the very same day as the IBM purchase of Q1, McAfee’s purchase of Nitro Security offers it similar capabilities. The SIEM vendor gives McAfee risk management and cross-infrastructure monitoring capabilities and will help it unify its portfolio through a more cohesive management console.

Close Date: AprilPrice: UndisclosedGiven the Nitro deal a few months later, McAfee’s purchase of Sentrigo makes even more sense than it already did. Sentrigo’s database activity monitoring capabilities will provide a more robust information protection component to the McAfee portfolio and the data gathered from it can be streamed through Q1 for more effective event correlation.

Close Date: July 6Price: UndisclosedNoted primarily for its endpoint protection suite, Sophos looked to round out its security capabilities with a pick-up of Unified Threat Management (UTM) vendor Astaro. The buy gives Sophos a greater footprint in the network security realm and will help customers cover more security layers without having to go to a different vendor.

Close Date: Sept. 23Price: $12.8 millionEncryption and authentication vendor Wave Systems expanded its horizons with a purchase of Safend, which develops port and device control systems, removable media encryption and content security. The deal gives Wave greater presence with data loss prevention (DLP) capabilities and also allows it to extend into healthcare and government markets.

Close Date: OctoberPrice: UndisclosedGFI Software was looking to bolster its offerings for the managed services segment it caters to buy picking up Monitis, a SMB-focused cloud monitoring solution that will give MSPs moving to the cloud a way to keep better tabs on the cloud environment.