Before the first cold email goes out, upload the same list to LinkedIn as a matched audience, run a cheap video ad to only those people, and start the sequence once the campaign's reach gets close to the matched audience size. The email then lands on a name they have already seen. The catch most versions of this advice skip: LinkedIn won't upload a contact list under 300 rows or serve one that matches fewer than 300 members, so the classic "100 names from Apollo" version doesn't run as described.
Why the first cold email has nothing to stand on
A stranger doesn't know you, your brand, or what you have done, and even a 50 word email can't explain the problem, why it matters and why you should fix it. On one mentoring call, a data visualization agency wanted to sell data warehouse work through outbound, and the education that offer needed would never fit in a first message. On another, a B2B team was planning outreach the usual way: find 100 prospects, then message them cold.
Our answer on both: add a stage between finding the prospect and contacting them. Show them your face, your name and one client result first.
How to set it up
- Upload the sequence list as a contact list. Use LinkedIn's template in Campaign Manager and keep its headers. Emails only match accounts with a verified address, and an audience can take up to 48 hours to build.
- Or upload a company list. It matches on company name, website, email domain or LinkedIn Page URL, and you can narrow it by job function or seniority.
- Run one short video. Thirty seconds: who you are, who you worked with, what changed for them. You are buying recognition, not clicks, so in our experience a reach or awareness goal is far cheaper than paying for website conversions.
- Untick Audience Expansion. LinkedIn turns it on automatically where available, extending delivery to similar members. You want the list.
When to send the first email
Watch reach, which LinkedIn defines as unique member accounts with at least one impression. When it approaches your matched audience size, most of the list has seen you. Campaign Manager's Audience Penetration metric, unique reach divided by target audience size, shows that share directly for audiences of 300 or more. LinkedIn notes delivery metrics are modeled and take 24 to 36 hours to appear, so read them directionally, and LinkedIn ties much of that modeling to its Audience Network, so we switch the Audience Network off for a list-only warm-up.
On our calls the warm-up ran from a few days to about 10 business days. For a high-value B2B offer with a 1,000 person list from Clay, we suggested emailing after 10 days of ads, and pulling anyone who had already signed up out of the sequence.
Then write the email as a follow-up, not an introduction. Skip "I'm the founder of" and lead with the result they may have seen. Ask for the conversation, as in the cold email CTA that gets replies.
The 300 member floor changes the math
Both list types need at least 300 rows to upload and 300 matched member accounts to run. LinkedIn recommends 10,000 or more emails, notes Matched Audiences may be smaller in the EEA and Switzerland, and requires location in every ad set, which can shrink it further.
So size the list for the match, not the send. LinkedIn recommends uploading at least 10,000 email addresses to help a contact list reach 300 verified matches, so expect a small share of a cold list to match. If your real target is 100 accounts, a contact list of those people alone won't get there. Upload a company list that covers the market they sit in, narrowed by job function or seniority, or a much wider ICP contact list. And if you planned a lookalike of the list, LinkedIn retired those in 2024; see LinkedIn lookalikes are gone.
The takeaways
- Upload your outbound list to LinkedIn and run a short video ad to only that list before the first email.
- Untick Audience Expansion so the ad stays on the list.
- Start the sequence when reach nears the matched audience size, usually a few days to about 10 business days in.
- LinkedIn needs 300 rows to upload and 300 matched members to serve. A 100 name list won't run.
- Write the email as a follow-up to the ad, not a fresh introduction.
Common questions
Can I show LinkedIn ads only to the people on my cold email list?
Yes. Upload the list in Campaign Manager as a Matched Audiences contact list, using LinkedIn's template, and select it in the ad set. LinkedIn matches emails only against member accounts with a verified email address, so not everyone on the list will match. Untick Enable Audience Expansion in the ad set, since LinkedIn turns it on automatically where it's available and it extends delivery to similar members.
What is the minimum list size for LinkedIn Matched Audiences?
LinkedIn says a contact or company list must have at least 300 rows to upload and must match at least 300 member accounts to be used in an active ad set. The maximum is 20 MB or 300,000 records. For contact lists, LinkedIn recommends uploading at least 10,000 email addresses to help reach 300 verified matches, so a short target list is usually better run as a company list.
How long does a LinkedIn contact list take to be ready?
LinkedIn says generating a contact or company list audience can take up to 48 hours, and on rare occasions longer. You can add a segment that is still building to an ad set, and delivery starts once it reaches 300 member accounts.
How do I know when the list has seen my ad?
Use the reach metric in Campaign Manager. LinkedIn defines reach as the number of unique member accounts with at least one impression. When reach gets close to your matched audience size, most of the list has seen the ad. The Audience Penetration metric, unique reach divided by target audience size, shows that share directly for audiences of 300 or more. LinkedIn notes these delivery metrics are modeled and can take 24 to 36 hours to appear, so treat them as directional.
How long should the LinkedIn warm-up run before the first email?
There is no platform rule. On our calls it has ranged from a few days to about 10 business days, depending on list size and budget. The signal to move is reach approaching the matched audience size, not a fixed number of days.