On 11/20/12, 3M Co (MMM) will trade ex-dividend, for its quarterly dividend of $0.59, payable on 12/12/12. As a percentage of MMM's recent stock price of $88.22, this dividend works out to approximately 0.67%, so look for shares of 3M Co to trade 0.67% lower all else being equal when MMM shares open for trading on 11/20/12.