Palo Alto Networks Inc. /zigman2/quotes/207599953/composite PANW -0.06% shares dove more than 13% in extended trading Monday after the security-software company reported softer sales growth than expected and cut its annual forecast. Palo Alto Networks reported a fiscal second-quarter loss of $73.7 million, or 75 cents a share, on revenue of $816.7 million, up from $711.2 million a year ago. After adjusting for stock-based compensation and other effects, the company reported earnings of $1.19 a share, down from adjusted earnings of $1.51 a share a year ago. Analysts on average expected adjusted earnings of $1.12 a share on sales of $844 million, according to FactSet. "Fiscal second quarter revenue was below our expectations primarily as a result of continued impact of sales incentives related to our Next-Generation Security products from our prior fiscal year," Chief Executive Nikesh Arora said in the announcement. "We have made progress to address this and have implemented several go-to-market programs to reignite our firewall sales growth." The company also decreased its forecast for the full year's adjusted earnings and revenue, while providing a quarterly forecast that came in short of estimates. For the fiscal third quarter, Palo Alto Networks forecast adjusted earnings of 96 cents to 98 cents a share on revenue of $835 million to $850 million. Analysts on average were expecting adjusted earnings of $1.25 a share on revenue of $873 million, according to FactSet. The company said it now expects annual adjusted earnings of $4.55 to $4.65 a share, down from $4.90 to $5 a share, and revenue of $3.35 billion to $3.39 billion, down from $3.44 billion to $3.48 billion. Palo Alto Networks also said it plans to execute an accelerated share repurchase of $1 billion with an unnamed financial institution. Palo Alto Networks shares closed with a 2.3% decline at $237.33, then plunged to less than $205 in after-hours trading following the announcement.