From Steamspy twitter:
https://twitter.com/Steam_Spy/status/587918028463038464
Lock if sold
Update:
https://twitter.com/Steam_Spy/status/588086767821131776
#GTAV owners on Steam: 1074894 ± 80049
It's really early number and it doesn't include copies sold outside Steam.
https://twitter.com/Steam_Spy/status/587918028463038464
Lock if sold
Update:
Update on #GTAV Steam owners: 1,146,914 ± 59,680.
It doesn't include non-Steam copies.
More data should be available tomorrow morning.
https://twitter.com/Steam_Spy/status/588086767821131776