"Q2's results were negatively impacted by margin compression in North America due to the investments in next day Prime delivery, which we continue to believe is an example of short-term pain for long-term gain," Moody's Amazon Analyst Charlie O'Shea said in an email statement. CEO Jeff Bezos said in the earnings release that the change has resulted in "a lot of positive feedback" and "accelerating sales growth." "Free one-day delivery is now available to Prime members on more than ten million items, and we're just getting started," Bezos said in the statement.