Shares in the cybersecurity group CrowdStrike were down some 20 percent in pre-market trading on Wall Street on Friday amid suggestions it was involved in a massive IT outage hitting companies and airports worldwide.

According to Oleg Gorokhovsky, founder of the Ukrainian online bank Monobank, the outage resulted from "an interaction between the CrowdStrike antivirus" software and the Windows operating system of US tech giant Microsoft, whose shares were down around three percent in pre-market trading.