Merck (MRK) is off 7 cents to $35.63 and a noteworthy trade this morning is a buyer of 8,000 Jan 40 calls at $1.25 on AMEX. It was tied to shares at $35.50, according to a source on the exchange-floor. It might close an existing position, as open interest is 33K and the third largest position in MRK options (behind the Jan 35 puts and Jan 45 calls.)