Why Leading Brands Still Bet on the Direct Mail Letter Format

For over a century, direct mail letters have anchored some of the most successful communication strategies. They’ve announced new products, confirmed trust between institutions and clients, and carried some of the most important messages ever sent. The format has evolved, but the impact hasn’t faded.

Official letter and envelope packages remain the most widely used format among direct marketers, accounting for nearly 70% of all direct mail volume. Despite common misconceptions driven by the increase in digital marketing, direct mail letters are not a relic of the past. They are a proven way to drive measurable results for a brand built on trust.

Why You Should Send Direct Mail Letters

Letters Are Trustworthy

Long before digital communication, brands developed loyalty and reputation through typed or handwritten correspondence. This heritage still matters.

When opening a traditional USPS letter-sized envelope (#10 or 6″ x 9″), consumers instinctively attribute credibility and importance to what’s inside. This professional appearance creates the perception that:

• The sender has an ongoing relationship with the recipient
• The content is critical, relevant, or potentially urgent
• It might include special offers, statements, or other crucial documents

The direct mail letter format is a great option if your campaign requires a personal, authoritative touch. 

Letters Improve Engagement

Unlike emails or digital advertisements that disappear with a swipe, direct mail letters stay in hand. And since they are personalized and private, enclosed letters allow for a more detailed, one-on-one conversation with the recipient.

This format also allows you to customize specific components by including additional inserts, such as brochures, coupons, or response forms, to enhance engagement.

USPS research has found that 9 out of 10 consumers engage with promotional mail, as neuroscience research has found that the physical action of holding print advertising plays an influential role in consumer decision-making and purchasing behaviors.

How to Design a High-Performing Direct Mail Letter

It all begins before the reader even sees your message.

Start with the Envelope

• Plain, official-looking envelopes often perform best for financial, B2B, or insurance communications where credibility is key.
• Branded or textured envelopes work well for consumer or retail brands looking to spark curiosity or delight.
• Foil stamping, embossed logos, or wax seals signal care and craftsmanship.more likely to respond.

Keep Your Message Tight, Clear, and Confident

• Choose paper stock that reflects quality without excess weight.
• Use brand-aligned typography for tone and readability.
• Keep your copy confident and concise, focusing on clarity over cleverness.

Signal Your Values

• Use FSC-certified or recycled paper and note it in your copy.
• Include a clear privacy statement to demonstrate trustworthiness.
• Emphasize your commitment to service, reliability, and purpose.

What Consumers Expect from Letters

Recipients can instantly tell when they’re being treated as a data point versus a person. To increase engagement and connect authentically:

• Write as though you’re talking to one individual, not a list.
• Anchor your story in emotion. Belonging, curiosity, trust, or relief work better than
  “Act now.”
• End with a clear call to action, such as scanning a QR code, calling a specific number, or visiting a personalized landing page.

Your letter should extend a conversation, feeling more personal than any digital retargeting advertisement.

How Leading Industries Use Direct Mail Letters

The direct mail letter remains a cornerstone across industries that rely on credibility, trust, and long-term relationships. While creative execution varies, the underlying strategy is consistent: personalized, well-crafted messaging drives measurable results.

Investment & Wealth Management

In highly competitive financial markets, digital channels are no longer enough to drive investor growth reliably. One investment platform faced declining returns from digital advertising and podcast conversions. To revitalize acquisition, Franklin Madison Direct developed a comprehensive offline strategy:

• Digital channels were underperforming, and the brand needed a cost-effective way to grow its investor base.
• FM Direct designed 20 unique data models and crafted an engaging direct mail letter package. The campaign launched with 120k modeled records, targeting 50k high-potential leads.
• The initial campaign achieved a CPA of 83% below the target, prompting the client to expand mail volume sevenfold. Strategic testing of creative packages and targeting models continued to deliver affordable CPAs, solidifying direct mail as a powerful new acquisition channel.

Insurance & Home Services

Letters are uniquely effective for policy renewals, client retention, and educational outreach. Formal typography, clear messaging, and humanized copy foster trust while encouraging timely action. A personalized note about service status or coverage often outperforms heavily branded promotions.

Retail & Consumer Services

Heavy stock, visually striking inserts, and multi-touch sequences turn letters into immersive brand experiences that increase sales. Variable data printing allows for tailored offers and personalization, strengthening first-time and repeat purchase intent.

Health & Wellness

Personalized appointment reminders, follow-ups, and wellness outreach demonstrate reliability and care. Thoughtful copy and design reinforce patient engagement and trust without overwhelming the recipient.

Across all industries, the direct mail letter’s ability to combine credibility, personalization, and storytelling makes it a uniquely high-performing channel, especially when digital strategies plateau or fail to deliver the desired ROI.

How to Elevate Direct Mail Letter Performance in 2026

Even seasoned mailers have room to grow. As you plan next year’s campaigns, test and refine these levers:

• Use Surround™ to sync digital and direct mail strategies for high-impact engagement.
• Go deeper with personalization, using consumer data to reference preferences or behaviors.
• Partner with a direct response marketing agency to help you navigate the creative and design elements, postal regulations, and printing and production processes.
• Always test your creative formats to find the one that performs the best for your message and audience.

When you treat your letter like an evolving strategy instead of a static format, you unlock new opportunities for acquisition, retention, and scale.

Letters That Last

Direct mail letters are a proven, evolving format that continues to outperform. In 2026 and beyond, the most successful marketers will be those who reimagine this classic medium as the most personal form of direct communication still standing.

At FM Direct, we’ve helped over 100 clients explore new direct mail concepts and reach millions of prospects. Are you ready to start your test?