Caterpillar (CAT, news, chart, volatility) is bucking the bullish trend Friday. It is the only stock among the Dow thirty not moving higher late Tuesday. CAT is down 72 cents to $59.17. In the options market, trading is active. 25,000 CAT puts and 15,000 calls have traded. Most of the put volume is in the October contracts with strike prices ranging from 50 to 62.5. According to an exchange floor contact, an investor sold 3,750 of the October 62.5/57.5 spreads and bought the same number of October 55/50 put spreads. In this case, the strategist might be banking profits in one spread after the 16.3 percent decline in shares of Caterpillar in September and also looking for additional weakness in the stock from now until October options expiration.