Cold Email Reply Rates by Company Age: What 600 Emails to SaaS Founders Showed (2026)

We sent 600 first cold emails to US SaaS founders and broke down who replied. All interested replies came from companies whose domain was under six months old. Here are the numbers, the caveats and what we changed.

I'm the founder of Selamly, an AI agent that finds companies, researches them and writes cold email for B2B founders. Before selling it to anyone, we used it on ourselves: 600 first emails to SaaS founders in the US. This post is the honest breakdown of who replied, with every number we have. The sample is small, so read it as a field note, not a law.

The short version

• 600 companies got a first email. 9 people replied (1.5%). 4 of them were interested (0.67%).
• All 4 interested replies came from companies whose domain was less than six months old when we emailed them.
• Among the 163 companies with a known domain older than six months, nobody replied at all.
• 213 Y Combinator companies: 3 replies, all "please remove me". 0 interested.
• Companies found on product launch sites and in founder communities converted best: 3 interested out of 68.
• Audience mattered more than signals: 3 of the 4 interested companies had no signal, and only 17 companies had a strong one.

What we sent, and to whom

Every company was a US B2B software company. The emails were short (two to four sentences), sent from warmed-up mailboxes on separate sending domains, one company at a time, during the recipient's business hours. No follow-ups are counted here: these are replies to the first email only.

Our first emails were not great. We changed the copy several times during the test, which is one more reason to treat the numbers below as directional.

Replies by company age

We looked up when each company's domain was registered and compared it with the day we sent the email.

The pattern surprised us. We expected older, established companies to be better buyers because they have budgets. They might be, but they did not answer a stranger's email. The founders who had just launched did.

Our reading: a founder in the first months after launch is actively looking for customers, reads their own inbox and is open to help. A company that has been around for years either has a sales team, has a process that works, or gets so much cold email that one more does not register.

Replies by where we found the company

Launch sites and founder communities are where companies show up in the week they launch. That is the same "just launched" moment the age table points to, seen from another angle.

Y Combinator companies were the clearest miss. Three replies, all asking to be removed. Well-funded, young companies are not automatically good prospects: many already have someone doing sales, and they are some of the most heavily emailed founders anywhere.

Did buying signals help?

Our product is built around timing signals: a new hire, funding, a launch, a public post about the problem. So we expected signals to drive replies. In this test they did not.

Only 17 companies had a strong signal, so this does not prove signals are useless. It shows something simpler: the right audience replied without a signal, and the wrong audience did not reply with one. For this market, the most useful "signal" was the launch itself.

Our approach now: find the right audience first, let replies narrow it, then use signals to time emails within it. Signals tell you when to write; they can't fix who you're writing to. That combination is what we're measuring next.

Generic addresses were not a dead end

Conventional advice says never email support@ or info@. Three of our four interested replies came from exactly those addresses.

At a company with three people, support@ is often read by the founder. That changes as companies grow, which fits the age pattern. We still prefer a person's own address when the company's website lists one, and we never guess addresses.

What we changed after this

• We stopped emailing Y Combinator companies from our own account.
• When we pick companies from our database, domains under 12 months old now come first, and among them sites that look like a live product (pricing page, sign-up, customer proof) beat "coming soon" pages.
• We add newly launched products every night instead of relying on older lists.
• For our customers, the first month became a discovery month: no follow-ups, a deliberately varied set of companies, and a breakdown like this one at 300 and 600 emails so we can narrow the audience in month two.

Caveats

• Four interested replies is a small number. A different month could look different.
• Our email copy changed during the test, and early emails were weaker.
• Domain age is a proxy for company age, not the same thing. A new domain can belong to an older team.
• These are SaaS founders in the US. Other markets will have their own pattern; the method (break down replies by every attribute you have) is what transfers.