On 12/21/12, Iron Mountain Inc (IRM) will trade ex-dividend, for its quarterly dividend of $0.27, payable on 1/17/13. As a percentage of IRM's recent stock price of $31.06, this dividend works out to approximately 0.87%, so look for shares of Iron Mountain Inc to trade 0.87% lower all else being equal when IRM shares open for trading on 12/21/12.