No. Send cold email from separate domains bought for that purpose, and keep your primary domain out of it entirely.
The reasoning is short, but the consequence is large enough to be worth spelling out.
What you are risking
Sender reputation is scored at the domain level. If cold volume from your primary domain generates complaints or bounces, the damage is not contained to the campaign — it attaches to the domain your entire company sends from.
That means invoices, quotes, contracts, support replies, calendar invites and every message your team sends to existing customers start landing in spam folders. And you may not find out from a report. You find out because a customer says they never got your email, and by then it has been happening for weeks.
Weigh that against the upside of using your main domain, which is essentially nothing. Cold prospects do not know your company. The domain carries no recognition with them, so it is not buying you trust; it is only exposing an asset.
What we do instead
Look-alike domains, registered for outbound only. If your company is at examplecompany.com, the sending domains are close variants — the kind of thing a real business would plausibly own.
Each one gets its own mailboxes, its own authentication records, and its own warmup before it touches a prospect. Volume is spread across them under a daily cap per inbox, which is also why more volume means more mailboxes rather than harder sending.
One detail that gets skipped often enough to be worth naming: each sending domain should redirect to your real website. A prospect who receives your email and types the domain into a browser should land on your actual site, not a parked page or an error. It costs one DNS record and it is the difference between looking like a company and looking like a spammer.
What happens when one goes bad
This is the real argument for separation. Domains do occasionally slip, for reasons that are not always your fault — a bad data source, an unlucky list, a shift in filtering.
When a sending domain's placement drops, it comes out of rotation and rests while the others carry the volume. If it does not recover, it gets retired and replaced. That is an ordinary Tuesday, and none of it touches your company email.
Run the same scenario on your primary domain and there is no rotation to fall back on and nothing to retire. You just wait, and hope.
The one thing to insist on
Whoever sets this up, make sure the domains and mailboxes are registered in your name, not the agency's. They are business assets and they should stay with you if the relationship ends.
An agency that registers your sending infrastructure in its own name has given itself leverage over something your business depends on. There is no good reason for it, and it is a fair question to ask before you sign anything.