The past year has been a stellar time to own homebuilders. Some of the biggest stock gains of 2012 came from homebuilding stocks -- and early in 2013, the trend looks likely to continue. But not for M/I Homes ( MHO). To be clear, MHO has participated in the homebuilder rally, climbing more than 86% in the last 12 months. More important, those gains have been built in an uptrending channel, a tight trading range that makes MHO's price action much more predictable. The problem for shareholders is that this stock broke down below trend line support in yesterday's session; the inability to catch a bid at support is a big deal for a stock in an uptrend. Even though other home stocks are correcting this week, none saw as big (or technically significant) a fall as the one in MHO. That's a big signal to equity investors that the gravy train is slowing down in for shares in February. Unless buyers wake up and this stock manages to recapture its uptrend later today, I'd recommend exiting MHO here.