B
Evidence Grade B
Graded
accuracy verified by the review judge
Safe to Cite
Current
77.1%
77.1% -- spf adoption rate for Tranco top-1K domains (2026-03)
77.1% of Tranco top-1K domains have published valid SPF records as of March 2026.
Attribution:
View source
Lighthouse Research Team
Last verified:
·
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Source verified
Evidence graded
Value
77.1%
Unit
Percentage
Data Vintage
2026-03
Entity
Sample Size
1,000
Evidence Quality
B
Strong, reliable evidence
Sourced from a well-regarded research firm or industry leader with transparent methodology and a reasonably large sample.
Single source - not yet corroborated
Score breakdown
Extraction
95
Source Trust
60
Citation Chain
20
Independence
30
Methodology
45
Freshness
95
Source
DMARCguard
Primary
Tier A
https://dmarcguard.io/research/spf-supply-chain/ ↗
Source Article
SPF Supply Chain 2026: Email Sender Market Share Across 5.5 Million Domains | DMARCguard
SPF Supply Chain 2026: Email Sender Market Share Across 5.5 Million Domains
Microsoft 365 powers 19.6% of SPF-enabled domains. First-ever email sender market share by SPF include, analyzing 3 million domains from Tranco Top Sites.
Study at a glance
Executive Summary
Microsoft 365 and Google Workspac…
Original Research
DMARCguard
· Original study ↗
Methodology
771 of top-1,000 domains publish valid SPF records
Methodology documented
Segmentation
Industrymarketing
Cite this stat
Plain Text
Tranco top-1K domains: 77.1% spf adoption rate. Source: DMARCguard (2026-03). Via Lighthouse Intelligence -- https://lighthousedata.io/data/spf-adoption-top1k-2026
HTML Embed
<blockquote cite="https://lighthousedata.io/data/spf-adoption-top1k-2026" style="border-left:3px solid #2563eb;padding:12px 16px;margin:16px 0;font-family:system-ui,sans-serif;background:#f0f4ff;"><strong>77.1%</strong> -- spf adoption rate for Tranco top-1K domains<br><small>Source: DMARCguard (2026-03) · <a href="https://lighthousedata.io/data/spf-adoption-top1k-2026" target="_blank" rel="noopener">Lighthouse Intelligence</a></small></blockquote>
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