Welcome to Namepros. Glad to see a newbie here who already has an offer on their domain... and who seems genuinely to want to learn how to safely and best negotiate through this possible transaction.
- Do a very thorough trademark search; I'm assuming you only tried the USPTO site for US trademarks? Go to the
WIPO trademark search site and input your term, it will show all trademarks known in the other countries of the world.
***Note: if it is definitely a single term (even though it's made-up), one search there should do it. But if it seems to be a portmanteau word, made up of two or more partial words (like Travelocity from travel + velocity, or Brunch from breakfast + lunch, etc), then make sure to separate it where the words seem to be separated, to see if there is a TM on that separated term as well. - For example, there are various TMs for 'chat gpt', but also one for 'chatgpt' all one word. So if your domain is something like Cardgen (just a random example), make sure to put it as one word into the search field... but after that delete it and put in 'card gen' as two words into a new search.
- With that search, you'll see whether any trademarks pre-date your registration. If they all come later than your reg, then that is at least one step closer to safety for you. Another step is to never put any content on your website or landing page that is similar to what any trademark holder uses their company for. You know, if they have a TM for that term for use in the waffle-maker niche, don't put waffle-maker ads or products on your site. You can still lose the domain for trying to profit off the trademark holder even though you bought the domain first... if you later try to profit from their business through your domain/site.
- A member above asked a very good question: why did you register this domain when you did? - Another step of 'being safe' is to know that you had no knowledge that this company was forming, or developing some service/product with this name, and you rushed to reg it long before they applied for their TM. Some details like that also enter into the discussion.
- As mentioned a couple times by members above, don't discount the value of your domain. You may have been able to get it for registration fee 10 years ago, but trends and fads and new tech arrive every day. If you happen to have a domain whose 'time has arrived' and is a perfect match for this large company... it may well be perfect for other companies also. Maybe they'd want to brand/trademark it differently though. But yes, it is not uncommon for a name that was worth reg fee 10 years ago to now be worth thousands, tens of thousands, or more $$$$$.
- Another piece of research you can do: go to the website DotDB.com and input your term. You'll see how many other extensions are now taken for your term. ***Note that often one person or company can own many of those extensions. So check and see what kind of a lander or website is on each of the other extensions. For example, if you own Zigliesch.com and you go to DotDB and see that it is taken in Zigliesch.net, Zigliesch.org, and 5 others, put all those into the url search bar at top of your browser to see what's on them. If your name is only taken in the .com, that means it probably has little attraction to other companies. Or if it is part of the domain string of many extensions and many other domains, you may discover a large array of potential buyers. Check it out and see.
- Also go to Namebio.com, input your term, and see if any other domains with that term have been reported as sold. Only a tiny, tiny, TINY portion of aftermarket domain sales ever get reported to Namebio, but it still archives a lot of sales and is a good starting point.
- Also input your domain, with extension, to the Godaddy appraisal tool. As an appraisal tool it is useless mostly - but the reason to do this is you will also see, down the right side and the bottom, whether Godaddy has ever sold a domain with that term in the past on their platform. It will list sales of similar domains.
There are a dozen more things you can research, also about your potential buyers and how they might intend to use this domain. Some companies pay millions, and tens of millions of dollars on a single domain. $12K sounds very good to me, for a vague brandable term... but that's on the surface. Take a look much deeper than the surface. 12K might turn out to be a fantastic price, or it might turn out to be quite low. We won't know until we know the name.
You're welcome to private message it to any of the old-timers here, trusted members who can give you more specific info/advice once they know the name. You can send it to me, too. We will not post it publicly here without your permission. To post a name publicly can result in non-member lurkers rushing to register a bunch of similar domains, and your term in other extensions, and spam your potential buyer with a whole bunch of other domains to buy. That can be annoying and even a turn-off to your buyer, who will wonder how all those people knew about the name...
Good luck! Nice to know you have a very motivated buyer, with deep pockets, who in fact wants to buy a domain that you don't even have a use for.
- Note that I did not use any form of AI for the above. Ha ha. Just my own grey matter and experience.