The Subject Line

Email Best Practices When Targeting Investors

The subject line is, in Fifth Rock’s professional opinion, the most influential element of an email. Yes, who an email is from, and the actual content are very important, but the decision to even open an email is often made from the subject line alone.

According to OptinMonster, 47% of email recipients open an email based on subject line alone. Even more powerful is the fact that OptinMonster also reports that 69% of email recipients mark emails as spam or junk based on subject line alone. That means your first priority when composing an email is developing a powerful subject line.

So…how do you do that? There are a million and one resources online that are cover the gamut of tips and tricks, and you must find the mix that is right for you and right for the content you are putting out into the world. However, if investors are your audience, the following 4 recommendations should be top of mind:

DO: Keep it brief, and we mean really brief

Most email software cut off subject lines at 50 characters, with spaces. For reference, a subject line with exactly 50 characters would be JAN 2023 Performance: Up 10% with Market Downtrend. In reality, this is a very informative subject line that encourages opens to learn more about why you’re up when the market is down. However, 50 characters is the maximum subject length allowed, so trimming it down to below the max would be a smart move.

How short should we go? Well, if you’re opening your email on your phone, the character cutoff is lower, around 40. HubSpot claims that 41% of all emails views happen on mobile, compared to 39% on desktop, so you should assume that, if you want your entire subject line to fit and be read on any device, you should actually be at or below that 40 mark. We went ahead and adjusted the subject example to accomplish this: +10% with Market Downtrend in JAN 2023

The quickest way to trim down your subject line is to lose punctuation and articles, rely on standard acronyms and industry jargon, use numbers and symbols to replace words and phrases, and focus on the single-most important topic or call-to-action.

DO: Use numbers and dates/times whenever you can

Investors and managers alike share one thing: a love of data. The numbers often make or break decisions in the industry, and they tell a story in a concise manner. Dates and times frame those numbers so they can easily be related to or compared with others. For those reasons alone, using numbers and dates/times in your subject lines is worthwhile.

If you need data to back it though, Campaign Monitor ran extensive A/B testing specifically to measure the effectiveness of subject lines with numbers. Their study concluded that subject lines with numbers garner 57% better open rates than subject lines without numbers. 

Using your performance data in your subject will, by far, pack the greatest punch when targeting investors, but if you’re marketing strategy includes covering general industry trends, something like 5 Crypto Market Trends You’re Overlooking would also be effective.

DON’T: Use salesy or “promise” words and phrases

Investments never come with a guaranteed ROI, and the last thing you want to do is allude to the idea that someone can receive something specific by reading your email. That’s a general marketing rule of thumb but avoiding being flagged by the regulators for false solicitation or scheming should be reason enough to avoid it too. 

A less terrifying but equally applicable reason to avoid being salesy or making “promises” is because it increases the chance of the recipient marking the email as spam. Long story short, inbox service providers like Outlook and Gmail and Yahoo used to use spamblockers to protect recipients from being targeted by hackers and schemes. Spamblockers looked for trigger language in your subject line and would send your email to spam instead of the inbox if it found a trigger. While spamblockers are now an outdated technology, the years of having emails sent to spam automatically has given the general public a Pavlovian response to manually mark emails as spam if they have trigger language. Thus, just best to avoid it, even if it isn’t the kind of thing that the regulators would flag.

For reference, here are some of the common spam triggers related to the finance industry:

  • Financially independent
  • Investment decision
  • Sent in compliance
  • Stock disclaimer statement / Stock alert / Stock pick
  • US Dollars
  • Save … / Double your …

DON’T: Include all caps or emojis frivolously

There is a time and a place for being visually creative with your subject lines. Marketing emails for investors are generally not the time or place. The main reason is that it leaves the door open for misinterpretation of the subject line, which can impact engagement.

Take the subject line MAJOR CHANGE to Portfolio Coming. There is a softer way to express this that is also more informative, but all the recipient will see is “major change.” Is the change good or bad? What impact is there to the specific recipient? Why is the change happening now? The problem is that all-caps leaves a lot to interpretation and you have no idea whether they will perceive it as urgent, rude, terrifying, or have a completely different response. The idea of email marketing is to direct the recipient, but if your subject line encourages random responses, then your engagement will be equally as random.

The same applies for subject line that has an emoji. Not only do different generations interpret specific emojis as different things, but there are certain industries and arenas where the use of emojis is simply considered unprofessional. Using emojis invites a lot of unknowns that can impact opens, and may even lead to bounces or being marked as spam, according to Markettailor. There are some universal emojis that do not leave a lot to interpretation, like a green up arrow or a red X or hollow/filled stars, but these should only be used when the situation specifically calls for them and when they can help with maintaining character counts.

CONCLUSION: Short, professional, and to-the-point

The most important thing to remember is that subject lines are purely a gateway to the email’s content. The goal is to encourage opens and engagement by being informative and enticing but also professional and concise. Keep it under 40 characters, lean on industry language and numbers, avoid trigger words or unnecessary formatting, and don’t rely on gimmicks. Combine these best practices with a strong “from” name and preheader, and you should see a high open rate across all your email marketing efforts.


Fifth Rock will cover email best practices in subsequent parts of this Email Best Practices When Targeting Investors series.