Amazon CFO Stepping Down

Updated from 4:24 p.m. EST

Just when Wall Street had finally quieted down about its numbers, Amazon.com (AMZN Quote) made an announcement that will surely have investors speculating anew.

The big online bookseller said Tuesday that its financial chief, Warren Jenson, would step down later this year. Jenson, who has served as CFO at Amazon since September 1999, didn't specify a reason for leaving, saying only that "I took this position with the objective of working with Jeff and the management team to bring Amazon.com to profitability" and that "it's the appropriate time for me to move on to a new set of challenges." ...