Averaged across 3,925 brands with 5+ placement observations
inbox 82.3%promotions 16.3%spam 1.5%
Spam placement is mostly driven by the sender (list quality, content, complaints), not the ESP.
11.1% of Outlook opens never fire the sender's tracking pixel (images blocked)
Based on 4,609 opens tracked. Open rates undercount real opens more than most senders realize.