Jim Cramer: Loss of Partnership With Costco Adds to AmEx's Challenges

Last week Costco announced that it would be ending its partnership with American Express due to high transaction costs. Starting next year, American Express will no longer be the exclusive credit card accepted by the retailer. TheStreet's Jim Cramer says people underestimated the importance of that relationship and as a result, shares have been down substantially over the past week. He says no one understood the magnitude of that relationship nor the risk potential of the relationship being broken. He further explains that AmEx's partnership with Costco has fueled credit card growth both domestically and internationally and that will no longer be a tailwind for AmEx.