Detailed phone screen with company HR rep followed by group interview scheduled at their convenience. In person interview is an appointment for at least half of the selected candidates - it's awkward when waiting in the lobby with another 6-10 people. It gets more awkward when everyone is parked in a conference room while a series of managers picks up a candidate and interviews them 1:1 in an adjacent conference room. While you're waiting your turn for a manager to come get you the HR person and a team 'Hiring Leader' make small talk with you and answer questions about day to day duties of the position.
If you are selected to make the next round you return with a group of about three quarters of the first group, again at a time of Amex's choosing. You are given three hours to review a suspicious case and write an SAR. If you have never done this, which I had not, use Google to find SAR examples and use the FINCen website where they have guidelines. He packet of information you have to evaluate is huge - maybe 15 pages of letter sized paper and 5 of legal size. NONE of it is labeled and it is full of acronyms and system output. Having call center, finance and even some IT background is helpful.
As mentioned, interviews are on a mass schedule so if you have a job, be ready to duck out without much notice. The group interview I attended was on a Friday morning and took nearly half a day. The writing assessment was the Monday after in the late afternoon. The choice you are given is attend or not so start laying the groundwork for being sick or your car malfunctioning once the HR phone screen is scheduled.