The drop comes after the virtual security provider received a rating of "caution" from a study conducted by information security research and advisory firm NSS Labs.
The study was the firm's first ever comparative analysis of breach detection systems.
FireEye, along with AhnLab, were given the lowest marks of the six vendors that were tested in the study.
NSS Labs tested how effectively malware could be caught by the security systems while also testing for stability and reliability based on the products price point.
The two company's that received cautionary ratings "offer limited value for money given the three-year TCO [total cost of ownership] and measured security effectiveness rating," according to the test results.
FireEye has since questioned the credibility of the test after having declined to participate in it.