The top equity options trade so far today is in Pfizer (PFE). Shares are down 34 cents to $21.24 and one of 22 Dow stocks trading lower after the pharmaceutical giant posted better-than-expected fourth quarter earnings and revs, but then guided estimates lower for the 2012 fiscal year. Morning options trades on the stock include 16,000 January 22.5 calls, sold at $1.04 per contract, and possibly a liquidating trade on the heels of the disappointing earnings news. Overall, trading in PFE is brisk. 61,000 calls and 21,000 puts traded. Meanwhile, implied volatility in the options on the stock is down 13.5 percent and probing the 52-week lows of 17.3 seen in late-May 2011.