Averaged across 3,825 brands with 5+ placement observations
inbox 82.1%promotions 16.4%spam 1.5%
Spam placement is mostly driven by the sender (list quality, content, complaints), not the ESP.
17.9% of Outlook opens never fire the sender's tracking pixel (images blocked)
Based on 1,374 opens tracked. Open rates undercount real opens more than most senders realize.