Stocks of cyber security companies were mixed Thursday, with a standout performance from Carbon Black, Inc. (CBLK) - Get Report in the regular session ahead of the announcement it's being acquired by VMware Inc. (VMW) - Get Report .

Among notable cyber security stocks, six rose while 12 fell.

Carbon Black shares (CBLK) - Get Report led the gainers, rising $1.75, or 7.69%, to $24.50. After the market closed, VMware said it is buying Carbon Black in an all-cash deal for $26 a share.

Elsewhere in the sector, SailPoint shares (SAIL) - Get Report rose 52 cents, or 2.35%, to $22.63. Tenable shares (TENB) - Get Report rose 43 cents, or 1.97%, to $22.30.

Among decliners, Splunk shares (SPLK) - Get Report fell $10.05, or 7.82%, to $118.41 in the wake of its latest financial results

Carbonite shares (CARB) - Get Report fell 53 cents, or 3.8%, to $13.40. CyberArk shares (CYBR) - Get Report fell $1.87, or 1.56%, to $117.83.

The Nasdaq Composite Index fell 28.82 points, or 0.36%, to 7,991.39.

Eleven cyber-security stocks outperformed the Nasdaq Composite while seven lagged.

Among sector ETFs, the ETFMG Prime Cyber Security ETF ETF (HACK) - Get Report  fell 13 cents, or 0.34%, to $38.38. The First Trust NASDAQ Cybersecurity ETF  (CIBR) - Get Report fell 17 cents, or 0.59%, to $28.87.

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