On 1/8/13, AT&T Inc (T) will trade ex-dividend, for its quarterly dividend of $0.45, payable on 2/1/13. As a percentage of T's recent stock price of $35.06, this dividend works out to approximately 1.28%, so look for shares of AT&T Inc to trade 1.28% lower all else being equal when T shares open for trading on 1/8/13.