It's not exactly time to run for the hills in shares of heavy equipment maker Caterpillar ( CAT), but we're not far off now. CAT has been getting plenty of attention (and not the good kind) after lowering guidance, announcing a price hike, and cutting jobs from its factory line. But early signs point to more bad news for shareholders. That's why I'm recommending that you stay away from this stock. >>5 Big Stock Charts You've Got to See to Believe Right now, CAT is in the early stages of forming a head and shoulders top, not a particularly good sign, especially since shares of the $56 billion firm are a lot closer to their near-term lows than their highs. The head and shoulders indicates exhaustion among buyers, so it tends to be a particularly difficult setup for longs to overcome. While CAT still hasn't formed its right shoulder, the trading implications are the same as long as shares fall through their $82.50 neckline. That's the signal the CAT is set to make a move lower. Lest you think that the head and shoulders is too well known to be worth trading, the research suggests otherwise: a recent academic study conducted by the Federal Reserve Board of New York found that the results of 10,000 computer-simulated head-and-shoulders trades resulted in "profits that would have been both statistically and economically significant." Don't get caught on the other side of shorts on this trade.