SEM = Search Engine Marketing
IMO, it can easily go close to 10k or even above because that term is very short and very hot, dot co or dot com, it's hot kw!! Get it, develop it, then don't sell if you have a strategy. SEM is very hot and will be volcanic!!! For example,
m.sem.co will do wonders for mobile advertising and marketing field. As it is a "closed" auction, outsiders cannot join in now, so hold on and you may own it soon, at around 8K, I guess. If you have the money, think hard & proper then decide!

It's my humble opinion and it's your major decision... but I think that domain can turn out to be a major money-maker soon.
P.S.: You said 9 hours, then probably it will not even go up to 4.5~5k because of the limited time and number of bidders. I think, if you've waited so long, then it's just a matter of time and you said you have the money too. It sure is a great domain in the right hands.