Yes, I checked which domains are connected to the interested buyers email. He seems to be a domainer, and the email he used to contact me is connected to about 50 undeveloped domains. I didn't see any "standout" premium domains in his portfolio. Since he is probably not an enduser, I am not expecting too much from this inquiry. He contacted me through the contact form on the registrar parking page (I didn't list it on a marketplace yet), so he must have found it through direct type-in.
Still not sure how much this domain could be worth and what I should try to go for. Looking at past sales for various "investment" related domains, it seems they usually went for minimum low $x,xxx, and often a lot more than that.