What is the quantitative impact of implementing DMARC on email deliverability and engagement?
Michael Ko
Co-founder & CEO, Suped
Published 9 May 2025
Updated 16 Aug 2025
6 min read
Many email marketers and security professionals ask about the concrete, quantitative impact of implementing DMARC (Domain-based Message Authentication, Reporting, and Conformance). While it's widely accepted that DMARC is crucial for email security, pinpointing exact percentage increases in deliverability or engagement can be challenging.
The truth is, DMARC primarily serves as a security protocol, giving domain owners control over unauthenticated email. However, its security benefits often translate into significant, measurable improvements in how your emails are perceived and delivered, ultimately affecting recipient engagement.
DMARC builds upon existing email authentication protocols, SPF and DKIM. It allows domain owners to publish a policy instructing receiving mail servers on how to handle emails that fail authentication and provides reporting on those failures. This is primarily a defense against email spoofing and phishing, which are major threats to brand reputation and recipient trust.
DMARC records allow the sender to instruct email providers how to handle messages that don't pass authentication. Without DMARC, even if SPF and DKIM are configured, a malicious actor could still send emails pretending to be from your domain, and recipients' inboxes wouldn't know how to reliably differentiate legitimate mail from fraudulent messages. This can severely damage your sender reputation and lead to your genuine emails being sent to spam folders.
By enforcing DMARC (e.g., with a policy of p=quarantine or p=reject), you effectively tell email receivers to quarantine or reject unauthenticated emails from your domain. This significantly reduces the volume of fraudulent emails circulating with your domain, thereby protecting your brand and improving the overall trustworthiness of your legitimate email streams.
Measurable improvements in deliverability
While DMARC's primary function is security, its impact on email deliverability is a significant secondary benefit. When your domain is protected by DMARC, particularly with an enforcing policy, mailbox providers (like Gmail and Yahoo) are more confident that emails originating from your domain are legitimate. This increased trust can lead to better inbox placement.
A key quantitative benefit comes from the reduction of email spoofing. If your domain is being spoofed, those illegitimate emails can generate spam complaints or hit spam traps, which negatively impacts your sender reputation. DMARC puts a stop to this, preventing malicious activity from dragging down your good name. Over time, as your sender reputation improves, you will observe a direct increase in your email deliverability rates.
DMARC provides detailed reports that help you identify and rectify any ongoing deliverability issues. This visibility is invaluable. For instance, a past case study (from 250ok, pre-acquisition) showed significant improvements in inbox placement and delivery speeds for a consumer brand after DMARC implementation. While hard, universal numbers are scarce due to varying email programs and sender reputations, the trend is clear: DMARC improves deliverability by fostering trust and mitigating abuse.
Before DMARC enforcement
Reputation risk: Vulnerable to spoofing, leading to potential brand damage.
Lower trust: Mailbox providers are less confident in your emails' authenticity.
Inconsistent delivery: Higher chance of emails landing in spam or being rejected.
After DMARC enforcement
Enhanced security: Protection against phishing and domain impersonation.
Improved trust: Mailbox providers recognize your emails as more trustworthy.
Better inbox placement: Higher likelihood of reaching the primary inbox, reducing spam folder delivery.
Boosting engagement and brand reputation
The link between DMARC and engagement is indirect but powerful. When emails consistently land in the inbox, rather than spam, recipients are more likely to see and interact with them. This forms a positive feedback loop: better deliverability leads to higher visibility, which drives engagement.
Quantitatively, some studies have shown an increase in unique clicks on DMARC-compliant emails. While exact figures vary, early data from a large dataset (930 million emails) indicated up to a 2x increase in unique clicks for emails that were DMARC compliant. This suggests that when recipients are confident about the sender's authenticity, they are more willing to open and click on emails.
Brand Indicators for Message Identification (BIMI) is another authentication standard that directly leverages DMARC and can boost engagement. BIMI allows your brand's logo to appear next to your email in supported inboxes, providing a visual cue of authenticity and trust. Since BIMI requires a DMARC policy of p=quarantine or p=reject, DMARC becomes a prerequisite for this engagement-boosting feature. Trials by Verizon/Yahoo showed that BIMI can indeed boost engagement.
The combined impact on engagement
DMARC helps emails reach the inbox, reducing the chance of them being caught in spam filters or blocked. When emails consistently arrive in the primary inbox, recipients are more likely to see them. The visual assurance of a legitimate sender (especially with BIMI) encourages more opens and clicks. This leads to higher engagement metrics like open rates, click-through rates, and ultimately, conversions. It also helps preserve your sender reputation, preventing you from appearing on a blocklist or blacklist, which would directly impact your ability to reach inboxes.
Strategic implementation for maximum impact
To realize the quantitative benefits of DMARC, proper implementation is key. Many companies start with a `p=none` policy, which only monitors email streams without taking enforcement actions. This allows you to collect DMARC reports and identify legitimate and illegitimate sending sources. Only after a thorough analysis should you move to a more restrictive `p=quarantine` or `p=reject` policy.
Ensuring DMARC alignment is crucial. Your SPF and DKIM authentication must align with your DMARC policy for your legitimate emails to pass checks. Misconfigurations can lead to your own emails being blocked or sent to spam, negating any potential benefits. Continuous monitoring of your DMARC reports is essential to ensure ongoing compliance and quickly address any issues. For more details on this, you can look at our guide to troubleshooting DMARC reports.
Always begin your DMARC implementation with a 'p=none' policy to gather data without impacting deliverability.
Analyze your DMARC reports meticulously to identify all legitimate sending sources and fix authentication issues.
Ensure that your SPF and DKIM records are correctly configured and align with your DMARC policy.
Gradually move to 'p=quarantine' and then 'p=reject' policies once you are confident about your email streams.
Common pitfalls
Jumping straight to 'p=reject' without proper monitoring, leading to legitimate emails being blocked.
Ignoring DMARC reports, missing opportunities to identify and address email authentication failures.
Failing to ensure alignment between DMARC, SPF, and DKIM, causing deliverability issues.
Not accounting for all legitimate sending services (e.g., marketing platforms, transactional email providers) in your DMARC policy.
Expert tips
Implement DMARC in stages, starting with monitoring, then quarantine, and finally reject.
Use DMARC reports to uncover hidden sending sources you might not have known about.
Combine DMARC with BIMI to visually verify your brand in the inbox, further boosting engagement.
Remember that DMARC is a security tool first, but its deliverability benefits are a powerful byproduct.
Marketer view
Marketer from Email Geeks says a case study published a few years ago showed improved inbox placement, faster delivery speeds, and better consumer engagement after DMARC was implemented for a brand.
2022-07-26 - Email Geeks
Marketer view
Marketer from Email Geeks says being spoofed can really hurt deliverability, and DMARC helps prevent that.
2022-07-27 - Email Geeks
Realizing the DMARC advantage
While providing exact universal percentages for DMARC's quantitative impact is difficult due to the many variables in email marketing and sender reputation, the qualitative and often measurable improvements are undeniable. DMARC serves as a critical security layer that directly influences trust, which in turn boosts deliverability and engagement. By preventing unauthorized use of your domain, you eliminate a major source of negative reputation impact, paving the way for your legitimate emails to consistently reach the inbox.
The quantitative benefits are realized through reduced spam complaints, improved sender reputation (and avoidance of blocklist or blacklist entries), higher inbox placement rates, and ultimately, better open and click-through rates. Implementing DMARC is a strategic investment that strengthens your email program's foundation, leading to more effective and secure communications.
