85% of top 1,000 sites publish DMARC, but only 69% enforce it

A DEV Community study checked the email DNS of the 1,000 most popular Tranco domains on 10 October 2026. 84.5% publish DMARC, 69.4% enforce it (quarantine/reject) and 47.4% reject outright. SPF is present on 89.6%, BIMI on 21.3% and MTA-STS on just 4.5%. Google Workspace hosts mail for 37.3% of domains, Microsoft 365 for 17.4%.

• 84.5% publish DMARC, 69.4% enforce it, 47.4% reject outright
• 89.6% publish SPF, 53.8% of them with hard-fail -all
• BIMI on 21.3% of domains, MTA-STS on only 4.5%
• Google Workspace hosts 37.3% of domains, Microsoft 365 17.4%