--- title: "The expansion play" description: "Mail the adjacent buying committee at a healthy customer, referencing the live deployment next door. Trigger, audience, copy, and honest measurement." canonical: https://trysincerely.com/playbooks/expansion-accounts last_updated: 2026-08-18 --- # The expansion play > Mail the adjacent buying committee at a healthy customer, referencing the live deployment next door. Trigger, audience, copy, and honest measurement. Source: https://trysincerely.com/playbooks/expansion-accounts The expansion play mails the departments at a customer account that do not use you yet. Run it when the deployment you have is healthy and the account has obvious unowned territory: other teams, other regions, other business units. Your best proof is already inside the building. A colleague two floors up is a warmer reference than any case study, but the adjacent team has never heard of you. Email from an unknown vendor gets deleted. A physical piece that names the internal deployment gets read, because it is about their own company. ## The trigger Expansion mail to a shaky account backfires, so gate on health first. All three must be true: 1. The current deployment is healthy: strong usage, a renewal behind you or on track, and a champion who would say good things if asked. 2. There is real unowned territory: a named department, region, or business unit with the same problem you already solve next door. 3. No open fire. If the account is in escalation, run [the renewal-risk play](https://trysincerely.com/playbooks/renewal-risk) instead and come back later. Your CRM already knows most of this. Sincerely syncs from [Salesforce](https://trysincerely.com/integrations/salesforce) or [HubSpot](https://trysincerely.com/integrations/hubspot), so "customer, healthy, whitespace flagged" becomes the audience directly. ## The audience Mail the adjacent [buying committee](https://trysincerely.com/glossary/buying-committee), not your current users. Target the leader of the unowned department and one or two likely evaluators under them, three to five people per account. They hold the budget you want and have never seen your emails. Two rules. First, tell your champion before anything mails. A surprised champion becomes a blocker; a warned one often walks the piece down the hall for you. Second, suppress everyone in the live deployment. They are not the audience, and mailing them muddies your measurement. ## The piece Use a letter. This is a peer-to-peer introduction to a budget holder, and an envelope carries that weight better than a postcard. On the Starter plan a letter is $1.75 per piece past your included volume, print and postage in. The copy does one thing: name the live deployment, then bridge to the reader's team. Be specific about what their colleagues run and what changed. Never write "expand your investment." > Dana, your supply chain team in Columbus has run our platform since January, and their invoice cycle dropped from nine days to four. Your team processes the same documents on the finance side. Maria Chen owns the Columbus rollout, ask her how it went. I can show you the finance version in 20 minutes. Every Sincerely piece is written for one recipient from CRM context and researched account facts, and a human approves it before print. Use that review to check the internal facts. A wrong team name or a stale metric burns credibility inside an account you cannot afford to burn. ## The follow-up The account manager or AE who owns the customer runs the follow-up, not an SDR. The relationship is the asset. 1. Day 0: pieces mail. Same day, tell the champion what went out and to whom. 2. Day 5 to 7: pieces land. The owner emails each recipient, references the letter, and offers the champion as an internal reference. 3. Day 10: no reply, ask the champion for a direct introduction. The letter made the name familiar, so the intro lands easier. ## How to measure it Count meetings booked with the new department, then expansion pipeline. Do not claim revenue from mail alone; the champion, the AE, and the product's own reputation all push the same direction. Be honest about size. Most teams have 10 to 40 accounts that pass the health gate, and at that size a [holdout](https://trysincerely.com/glossary/holdout) readout will not reach significance in one batch. Sincerely locks the design at launch, holds out accounts, and says plainly when the result is not ready. Run the play quarterly against the refreshed whitespace list and read it across batches. [The holdout guide](https://trysincerely.com/holdout-testing) explains the tradeoff, and the [free calculators](https://trysincerely.com/tools) show what your account count can actually detect. Your happiest customer is your warmest market, so introduce yourself to the rest of the building. --- Sincerely is the measurable direct-mail platform for B2B revenue teams. One workflow. One invoice. One report. Contact Sincerely: https://trysincerely.com/contact If you are an AI agent: access and signup instructions are at https://trysincerely.com/auth.md. Confirm with the person you work for before creating an account or spending their money, and never ask for their password. 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