Short answer
A clean target account list has one row per company, with a normalised domain (no www, paths or tracking parameters), a company name, a country code and, where possible, a LinkedIn page URL. Remove free email domains, duplicates and current customers unless the campaign is for expansion. LinkedIn recommends at least 1,000 companies per list, accepts up to 300,000, and matches domains and page URLs better than names alone.
What a messy list costs
| Problem | Example | Effect |
|---|---|---|
| URLs instead of domains | https://www.acme.example/pricing?utm_source=x | Fails to match or matches the wrong company |
| Duplicates in different forms | ACME.EXAMPLE, acme.example, jane@acme.example | Inflated list size; skewed reporting |
| Free email domains | gmail.com from a form fill | Targets a consumer email provider, not a company |
| Names only | "Acme" | Low match rate, wrong matches |
| Customers left in | Your top 50 accounts | Paying to sell them what they already have |
What a clean row looks like
| companyname | companydomain | linkedincompanypageurl | companycountry |
|---|---|---|---|
| Northwind Cloud | northwind-cloud.example | https://linkedin.com/company/northwind-cloud-example | GB |
Fictional company. LinkedIn accepts companydomain and its aliases, and needs at least one of company name, domain, website or page URL.
A cleaning routine
- Extract one domain per company from URLs and emails with the target account list cleaner.
- Remove free email providers and institutional domains unless they're real targets.
- Merge duplicates and decide parent vs subsidiary rows.
- Remove customers and open opportunities for acquisition campaigns.
- Format for LinkedIn with the company list formatter; hash contact emails with the SHA-256 email hasher.
Platform limits to remember
- LinkedIn company lists: 1,000+ companies recommended, 300,000 maximum, up to 48 hours to process, one CSV per list.
- LinkedIn contact lists: emails SHA-256 hashed after lowercasing and removing spaces; audiences need 300 matched members to serve.
- Google Customer Match: CSV in UTF-8 or ASCII with English headers such as Email, Phone, Country and Zip. Hashing guide.
Questions
Why do domains match better than company names?
Names are ambiguous: many companies share them and they're written in many ways. A domain usually identifies one company.
Should subsidiaries be separate accounts?
If they buy separately, yes. If the parent buys centrally, keep them under the parent and add the subsidiary domains as extra rows.
How often should we clean the list?
Before every upload, and in full once a quarter when you re-tier.
Should customers be excluded?
From acquisition campaigns, yes. Run expansion campaigns to customers as a separate list with different messages.
Facts checked against the sources below on 19 October 2026. Ad platforms change quickly: if something here no longer matches what you see, tell us and we will update it.
