Summary
The consensus from various email marketing experts, resources, and documentation leans towards the idea that using a dollar sign ($) in an email subject line doesn't automatically guarantee spam issues, but it does carry some risk. Modern spam filters are sophisticated, considering factors beyond individual symbols. Email quality, sender reputation, authentication (SPF, DKIM, DMARC), and engagement rates are paramount. Many recommend testing subject lines to observe the impact. Some sources advise caution and suggest that while a dollar sign may not always cause problems, it's best used sparingly and within a relevant context. Others directly state that using special characters, including dollar signs, can act as spam triggers and harm open rates. Key documentation highlights that email senders should avoid practices, such as using special characters, that spam filters flag as unwanted messages. Good sending practices, including personalization, segmentation, and respecting recipient preferences are vital. It's important to note that while SpamAssassin has a rule related to excessive monetary symbols, it mainly concerns the email body and has a low score.
Key findings
- Not a Guaranteed Trigger: Using a dollar sign in the subject line isn't a guaranteed spam trigger, but is a higher risk approach.
- Holistic Evaluation: Modern spam filters assess various factors, including email quality and sender reputation, rather than solely relying on specific symbols.
- Authentication is Key: Proper email authentication (SPF, DKIM, DMARC) is crucial for deliverability.
- Context and Moderation: If used, a dollar sign should be relevant to the content and used sparingly.
- Potential Negative Impact: Some sources advise that using dollar signs can still negatively affect deliverability and open rates.
- Test Your Emails: Testing your emails to assess deliverability and how they are delivered will help. This will confirm your deliverability with your audience.
Key considerations
- Focus on Quality: Prioritize creating high-quality, engaging, and relevant email content.
- Establish Reputation: Maintain a good sender reputation by adhering to email marketing best practices.
- Authenticate Your Emails: Implement SPF, DKIM, and DMARC to improve email deliverability.
- Test Your Subject Lines: Experiment with different subject lines, including those with and without dollar signs, to measure their impact.
- Segment Your Audience: Segment your audience and personalize email content for better engagement.
- Comply with Regulations: Adhere to email marketing regulations (e.g., GDPR, CAN-SPAM) to maintain trust and avoid penalties.
- Consider Alternatives: Evaluate whether using a dollar sign is necessary or if alternative phrasing can achieve the same goal without the potential risk.
What email marketers say
11 marketer opinions
The impact of using a dollar sign ($) in email subject lines on deliverability is complex and not a definitive 'yes' or 'no'. While some sources suggest that it can act as a spam trigger, especially if used excessively, modern spam filters are more sophisticated than simply flagging emails based on a single symbol. The consensus leans toward the idea that overall email quality, sender reputation, authentication practices (SPF, DKIM, DMARC), and engagement rates are more critical factors. Many marketers advise testing subject lines to see how they affect deliverability and open rates, and focusing on providing value and relevance to the audience.
Key opinions
- Not a Guaranteed Trigger: A single dollar sign in a subject line is unlikely to automatically trigger spam filters.
- Context Matters: The context of the email and the overall quality of the content play a significant role in deliverability.
- Reputation and Authentication: Sender reputation, proper authentication (SPF, DKIM, DMARC), and engagement rates are more important factors.
- Modern Filters: Modern spam filters are more sophisticated than simply blocking emails based on special characters.
- Testing is Key: Testing subject lines with different symbols is recommended to assess their impact on deliverability and open rates.
Key considerations
- Overall Email Quality: Focus on providing value and relevance in your emails to improve engagement and avoid spam filters.
- Sender Reputation: Maintain a good sender reputation by following best practices and avoiding spam-like behaviors.
- A/B Testing: Use A/B testing to experiment with different subject lines and measure their impact on deliverability and open rates.
- Balance and Restraint: If using a dollar sign, use it sparingly and naturally within the context of the subject line.
- Authentication: Ensure proper email authentication (SPF, DKIM, DMARC) is in place to improve deliverability.
Marketer view
Email marketer from Sendinblue explains that using a dollar sign ($) in your subject line can be seen as a 'spam trigger' and hurt your open rates, and recommends testing.
26 Apr 2023 - Sendinblue
Marketer view
Email marketer from SuperOffice says that using symbols such as the dollar sign may trigger spam filters and negatively impact the performance of the email campaign, and suggests testing.
5 Apr 2025 - SuperOffice
What the experts say
4 expert opinions
The experts generally agree that a dollar sign in a subject line is not a direct, guaranteed cause of spam issues. One expert states 'No', and another expert with a marketer elaborates that while a SpamAssassin rule exists related to monetary terms, it's complex, low-scoring, and primarily concerned with the email body, not the subject line. They further highlight that a high spam score due to this rule likely indicates larger underlying deliverability problems. Spamresource acknowledges it as a higher risk approach depending heavily on IP, content and authentication and therefore careful consideration should be taken before using. Word to the Wise recommends that good sending practices and authentication are key to inbox placement.
Key opinions
- Not a Direct Trigger: A single dollar sign is unlikely to directly trigger spam filters.
- Low-Scoring Rules: SpamAssassin rules related to monetary terms are typically low-scoring and not focused on the subject line.
- Larger Problems: If a 'dollar sign' triggers a high spam score, it suggests other underlying issues.
- Higher Risk: Spamresource mentions it is a higher risk approach, with all the correct IP, content and authentication checks needing to be in place.
Key considerations
- Authentication: Ensure proper email authentication (SPF, DKIM, DMARC) is in place.
- Good Sending Practices: Focus on good sending practices and recipient preferences for overall deliverability.
- IP Reputation: Ensure your IP Reputation is not bad or this will impact deliverability.
- Other Factors: Deliverability depends on a variety of factors, including sender reputation and content quality.
Expert view
Expert from Email Geeks simply answers 'No' to the question regarding dollar signs causing issues in subject lines.
5 Apr 2022 - Email Geeks
Expert view
Expert from Email Geeks and marketer from Email Geeks discuss the LOTS_OF_MONEY rule in SpamAssassin. Laura mentions the LOTS_OF_MONEY rule has a low score of 0.01, and that if THAT makes your mail be marked as spam, then you have much, much bigger problems. Laura states the rule is more complex than mentions a $ in the subject line and it wholly does not apply to the question that was asked, and Louis agrees it doesn't search the subject at all.
3 Nov 2024 - Email Geeks
What the documentation says
4 technical articles
The documentation provides mixed signals. SpamAssassin states a rule exists for excessive monetary symbols but focuses on the email body and carries a low score. RFC 5322 indicates no technical restrictions on using special characters in subject lines, leaving interpretation to receiving systems. However, both Microsoft and Google recommend avoiding excessive use of special characters, including the dollar sign, as they may trigger spam filters, while highlighting the importance of SPF, DKIM, and DMARC setup for deliverability.
Key findings
- SpamAssassin Focus: SpamAssassin's LOTS_OF_MONEY rule focuses on the email body and has a low score.
- RFC 5322 Flexibility: RFC 5322 places no technical restrictions on special characters in subject lines.
- MS and Google Caution: Microsoft and Google advise against excessive use of special characters in subject lines.
- Authentication Importance: Microsoft and Google highlight the critical role of SPF, DKIM, and DMARC for email deliverability.
Key considerations
- Minimize Special Characters: Consider limiting the use of special characters, including the dollar sign, in subject lines.
- Contextual Relevance: If using special characters, ensure they are relevant to the content and used sparingly.
- Implement Authentication: Prioritize implementing SPF, DKIM, and DMARC to improve deliverability.
- Follow Best Practices: Adhere to email sending best practices to maintain a good sender reputation.
Technical article
Documentation from Google advises that bulk email senders avoid practices that spam filters commonly use to identify unwanted messages. This includes, but is not limited to, the use of special characters and symbols in the subject line.
25 Aug 2024 - Google
Technical article
Documentation from Microsoft Bulk Email Senders Guidelines recommends avoiding excessive use of special characters and symbols in the subject line, including the dollar sign, as it may trigger spam filters. It is also very important to ensure SPF, DKIM and DMARC records are set up correctly.
9 Nov 2022 - Microsoft
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