Norton antivirus software maker Symantec Corp has agreed to sell its data storage unit, Veritas, for $8 billion to a group led by Carlyle Group LP as it seeks cash to turn around its core security software business.

The deal, the biggest US leveraged buyout this year, will give Symantec much-needed funds to compete in the cyber security market with companies such as Microsoft Corp, Intel Corp and Kaspersky Labs.

Shares of Symantec, which also reported weak quarterly results on Tuesday, fell as much as 6 percent.

Symantec has been facing headwinds as weak PC sales hurt demand for its security software, which comes bundled with computers. Demand for antivirus software has also fallen as users turn to advanced products for protection against sophisticated cyber attacks.

"Now they really get a new lease on life in terms of focusing on their core security DNA as the Veritas storage piece has been a massive black cloud on the Symantec story for a decade," FBR Capital Markets analyst Daniel Ives said.

Symantec is expected to use the proceeds to make inexpensive acquisitions as lofty valuations leave few security companies within its reach.

"If you think about potential acquisition candidates, those will be names like Proofpoint, Qualis, FortiNet Inc as well as a host of private companies," Ives said.

Symantec has long stayed away from network security products, which protect large amounts of data from online threats.

The fast-growing market is dominated by companies such as Palo Alto Networks Inc, FireEye Inc and Check Point Software Technologies Ltd.

"We don't expect them to shift to network security. It seems like they are not well positioned for that," William Blair & Co analyst Jonathan Ho said, adding that one area of growth could be security analytics.

Symantec could leverage its large customer base to collect data and use analytics to determine if there are indications of security breaches to provide better protection, Ho said.

Symantec, which bought Veritas for $13.5 billion in 2005, said it expected about $6.3 billion in net proceeds. The sale is expected to close by Jan. 1. The buyer group includes Singapore's sovereign wealth fund GIC.

Symantec also raised its stock buyback program by $1.5 billion.

Reuters reported earlier on Tuesday that Symantec would sell Veritas to Carlyle.

Revenue from Veritas, which accounts for nearly 40 percent of Symantec's revenue, fell 10 per cent in the first quarter.

The company also reported lower-than-expected revenue and profit for the quarter and forecast second-quarter earnings and revenue below analysts' expectations.

Symantec shares were down 5.8 per cent at $21.59 in afternoon trading. – Reuters