In its fifth largest acquisition ever, Big Blue scores a major spot in the security services market IBM Corp. has closed its US$1.3 billion acquisition of security vendor Internet Security Systems Inc.The acquisition, which closed Friday, is the fifth-largest in IBM’s history.By purchasing Atlanta-based ISS, IBM gains a strong position in the $22 billion managed security services market, which IBM sees as strategic to its future growth. ISS will retain its Atlanta offices and will be run as a business unit within IBM’s Global Services group. The ISS business unit will be led by Thomas Noonan, formerly the CEO of ISS. No layoffs are planned as a result of the deal.IBM plans to maintain the ISS Proventia and Managed and Professional Security Services offerings and to eventually integrate them with other products in its portfolio.The security industry is undergoing a round of consolidation as early leaders are being snapped up by larger companies. In June, EMC Corp. announced plans to purchase RSA Security Inc., a deal estimated at about $2.1 billion. Technology Industry