US Local Media Brand · US Local Media Brand
A Cold 50,000-Contact List, Relaunched to a Sustained 50% Open Rate
Client Snapshot
A US-based local media brand running a city-guide and concierge newsletter. They had collected a large subscriber list over time but had never mailed it consistently, so the audience had gone cold. They came to us to launch the newsletter on beehiiv without burning the list or their domain reputation in the process.
The Situation
The list held roughly 50,000 contacts, and none of them had heard from the brand in a long time. There was no send history and no sender reputation on the new publication, and authentication had not been set up. Mailing a cold list that size in one blast is one of the fastest ways to land on a blocklist. Complaints spike, and mailbox providers throttle the domain until the whole list is unusable. The brand needed the audience reactivated, but one wrong move early would have cost them the entire asset. The underlying data was messy too: a combined raw file of about 91,000 records full of duplicates and dead addresses.
What We Did
We treated sender reputation as the thing to protect and built the launch around a slow, monitored ramp.
Instead of sending from the root domain, we authenticated a dedicated sending subdomain with SPF, DKIM, and DMARC. That way any early spam complaints from a cold list could never touch the brand's day-to-day business email. We cleaned the list before anyone received a message, deduplicating the combined records and running bounce verification down to a clean base. Then we warmed the domain with an automated daily seed-list workflow, built on a beehiiv API integration so it ran without someone having to remember to send manually, and connected Google Postmaster Tools to watch the spam complaint rate in real time.
The launch itself opened at about 1,000 emails a day and stepped up gradually, most-engaged contacts first, with a standing suppression segment for anyone who unsubscribed or bounced. The decision that mattered most was refusing to rush. Every volume increase was gated on what Postmaster showed, not on the calendar.
The Results
Over the launch window, December 2025 through March 2026, across 36 campaigns:
- 50.33% average open rate across 82,755 emails delivered, with individual sends reaching as high as 78.97%
- A 0.001% spam complaint rate: one complaint across all 82,755 sends
- 100% delivery to Google inboxes, with a strong Postmaster reputation held throughout the ramp
- 11,058 unique clicks at a 26.56% click-to-open rate
- A durable engaged core of roughly 12,000 subscribers emerged from a list that had generated no engagement at all before the launch
Formula Inbox launched an email list with tens of thousands of subscribers that we had let go cold and hit an incredible 50%+ open rate. Their depth of knowledge on strategy and deliverability was the difference maker. Kind, sharp, and genuinely cared. Looking forward to working with them again.