Unpacking Cumulo9’s 2025 essential email insights report

The 2025 essential email insights report is here.

Email remains one of the most effective and reliable channels for business communication, particularly for delivering payslips, invoices, notifications and other essential messages. Now in its 5^th edition, Cumulo9’s essential email insights report 2025 brings practical benchmarks and strategic guidance for organisations that depend on essential email to connect with customers, staff and stakeholders.

Importance of this report

With inboxes becoming increasingly crowded and privacy settings more restrictive, email performance is facing greater challenges. This report focuses specifically on essential email, rather than campaign email, to provide insight into the essential communications that recipients actively engage with.

Based on millions of essential emails sent across Australasia, Cumulo9’s latest edition provides a clear picture of what has changed and how organisations can adapt. With a 99.5% deliverability rate via C9 Transact, the report presents a strong view of high-performing essential email in action.

What’s new in 2025

This year’s edition reveals several first-time trends:

• Mobile open rates have declined for the first time on record now sitting at 64.4%, down from 69%
• Essential email open rates have decreased slightly after multiple years of growth
• There is increased adoption of SPF, DKIM and DMARC for authentication
• Gmail and Microsoft have implemented stricter sender verification requirements

These developments highlight a shift in user behaviour and underline the importance of strong email infrastructure to maintain visibility and trust.

Key insights

One of the most significant findings in this year’s report is the financial impact of undelivered email. A non-delivery rate of just 0.89% could result in thousands of dollars annually in fallback print and postage costs.

The report also notes:

• Tuesday remains the highest performing day for essential email, with open rates reaching 72.5%
• Click-to-open rates have declined slightly to 6.2%, reinforcing the importance of concise, high-value content
• While mobile-first design is still relevant, rising desktop usage suggests testing across platforms remains essential

Actions an organisation can take to benefit from this report

The data provides a clear action plan for organisations looking to improve email effectiveness:

• Review authentication protocols and ensure DMARC is active
• Test alternative send times, including off-peak hours
• Use specific subject lines and well-positioned calls-to-action
• Maintain accurate and up-to-date contact lists to reduce bounce rates

These steps are especially important for transactional messages such as invoices, statements and critical updates, where delivery and engagement are essential.

The email landscape continues to evolve, and essential email remain a vital part of business communication. The 2025 report offers timely insights to help you refine your strategy, maintain compliance and improve engagement.

Download the full report here.

Don’t have time to read the report right now? Check out the video interview with Cumulo9 CEO Chris Hogg as he discusses the 2025 report highlights.

Are you Interested in finding out more? Contact our team with any questions or for more information.