Per ICANN rules, 2 and 3 letters domains cannot be of trademarks issues. This is because there are many companies in the world that can have the initials DHI or SSK etc... It can be a university, a company, website, corporation, a channel, a band etc...
Facebook paid 7 million dollars to purchase FB.com which belonged to the Farmer's Bureau. A nice sale i must say
But there are no problems with trademarks.
Where you could have a problem, is if you have a domain like IBM.com , while IBM is the known company, you could sell it to them or keep it. But you can have a problem if you build a website on IBM.com ( your domain ) insulting, criticizing or competing IBM Corp directly. Then yes, they can come against you. But if you build a website selling wines, they can't do anything.
So there are NO problems with trademarks , unless stated above. But as a domain alone, there are no issues with 3 letters. Because it could be anything with 3 letters.
Trademark issues are more present in longer domains, such as Facebooksucks.com etc... Where you just can't defend the fact that you registered this by mistake ;)
Domain is still for sale and looking for a quick deal at 10,900$us. really cheap for what it is.
Estibot.com appraisal is at 41k$!
Let me know!