A major weight on both Palo Alto's and Fortinet's GAAP earnings is stock-based compensation. Palo Alto's stock-based compensation rose 76% to $112.7 million last quarter and gobbled up a third of its revenue. That big increase, which caused a wider-than-expected GAAP loss, was the main reason the stock fell more than 10% after its earnings report on May 26. Fortinet's compensation expenses rose 63% to $30.8 million, but that only accounted for 11% of its total revenue.