Yes, an eager investor might interpret that as acceptance.
>1. The investor says “I’m in for [offer].”
>2. The startup says “Ok, you’re in for [offer].”
You'll notice that the startup has only repeated back what the investor said, correcting for the inverted subject-verb and adding a customary signal opening. The startup has confirmed receipt of the investor's signal.
>3. The startup sends the investor an email or text message saying “This is to confirm you’re in for [offer].”
The startup confirms receipt on a secondary channel.
