The CAN-SPAM Act (2003) is the United States law for commercial email. It doesn't require permission before emailing, so cold email is legal in the US, but it sets rules every commercial email must follow, business-to-business included.
The main rules
- Honest header information: the From name, address and routing must identify the real sender.
- No misleading subject lines.
- A valid physical postal address of the sender in every email.
- A clear way to opt out, honoured within 10 business days, and no charge or hoops to do it.
- Responsibility: you're liable even when someone else sends on your behalf.
Penalties
The FTC can fine each separate email that breaks the law, at tens of thousands of dollars per email.
In practice for cold email
Use real names and domains, an honest subject, your business address in the signature, and an easy opt-out that stops all further email. mailzy can add your business address to its automatic signature and stops all email to anyone who asks to be removed. This isn't legal advice; check with a lawyer for your situation.