The combined market share in the world wide security software market for the top five vendors – Symantec, McAfee, Trend Micro, IBM and CA – has dropped to 44% in 2010 from 60% in 2006, according to IT research firm Gartner.

In 2010, Symantec led the $16.5bn market with a share of 18.9%, followed by McAfee with 10.4%, Trend Micro 6.3%, IBM 4.9% and CA with 3.8%.

The share of Symantec has come down nearly by half in 2010 compared to 2006, while other four saw a marginal decline in the share.

Gartner principal research analyst Ruggero Contu said the information security market is in a continuous state of consolidation, but even fairly intense merger and acquisition (M&A) activity has not stopped the market from being very fragmented.

Gartner said that while M&A activity been a constant factor, the market is far from reaching a consolidated status, i.e. in which more than 60-70% of the market is owned by the top five vendors.

The main reason for this trend is that established leaders are losing market share to smaller players, many of which were start-ups that developed new offerings to meet newly introduced threats and vulnerabilities, or they implemented a successful go-to-market strategy, built themselves a niche presence and gradually took market share away from incumbent vendors.

"We expect more consolidation to take place place, along with innovations being introduced by new additions to the market," Contu said.

"The security market continues to provide good growth opportunities for both established players and start-up companies, and the market landscape remains fairly dynamic with many competitors."