Four credible sources published cold email reply rates in the last year. They differ by more than seven times, and almost none of the difference is performance.
Reply rate
Divided by what
Sample
0.45%
replies divided by emails sent, auto-replies and bounces excluded
7,530,489 emails
0.74%
replies divided by emails sent, median
850M+ emails
2.09%
replies divided by unique contacts, auto-replies included
2M+ emails
3.43%
denominator not disclosed
not disclosed
All four are truthfully reported and none of them are comparable. An agency quoting you the highest of these is not lying, it is dividing by something different.
Around 45% of replies to cold outbound are auto-replies and out-of-office notices. So a reply rate quoted without saying whether those count could be half machines. Ask what the denominator is. It is the only question that makes the number mean anything.