EMC Corp. (EMC) has seen an increase in call buying in recent trading. The November 13s are the most actives, with more than 16,500 contracts traded and 93 percent hitting on the offer. Open interest is 18,655, suggesting some possible closing trades. However, check the open interest Monday because, with shares up 28 cents to $11.74, it hints at speculative call buying in anticipation of a rally in EMC at some time before the November options come off the board (three weeks).