I am looking at past sales recorded for .Biz, not promising really. Speaking about premium names...but there is always an exception, overall high-quality keywords do not yield much return in comparison to other top extensions. So I just skip .biz.
Sport.biz $13,000
Hyip.biz $500
allgames.biz $70
Cashout $136
Well so many sales, but I think overall sale price is low, considering the premium terms.
While some one-word .biz domains become available; they are not worth much beyond regcost, because the super-premium sales were not that promising.
and it looks like these sales are end-user sales. this makes selling .biz name in resale market somewhat difficult.