After 23 years with American Express (NYSE:AXP), CFO Dan Henry is resigning from the company, but will stay on to assist in the hiring and transition processes, CEO Kenneth Chenault announced in a letter today.

According to Chenault, discussions with Henry have been ongoing "over the last few months" to ensure today's announcement was made at "the right time."

Henry has held the CFO position with American Express since 2007. Prior to his promotion to CFO, Henry served as head of the U.S. consumer, small business, and merchant service group, after 10 years as comptroller. In describing Henry's contributions over his American Express career, Chenault said, "Under his leadership, we continued to develop an outstanding team of professionals and strengthen an organization that is critically important to the success of our business."

According to the letter, the process of finding a new CFO is "likely to take a couple of months."