Anti-malware Vendor Market Share Report by OPSWAT
OPSWAT analyzed the market share of 64 anti-malware vendors for their August 2015 report, and the top three anti-malware vendors in their data are Avast at 16.3% market share, Microsoft at 15.7% [without counting Windows Defender] and Malwarebytes at 14.5%. These numbers reflect only those installations where Real-Time Protection is enabled.
https://www.opswat.com/resources/reports/anti-malware-market-share-security-august-2015
