I applied end of October and received an email from HR inviting me to two telephone interviews beginning of December, so don't worry if it has been ages and they haven't gotten back to you, it's a good sign. Two telephone interviews for me personally, was purely competency and motivational but they do ask about a recent article you read, so definitely find some good articles! For motivational, know why you want to work in the financial industry and have some unique answers for "Why JPM?". For competency, it's all pretty standard, always use STAR method and definitely go in to detail so they don't have to continuously push you. Be prepared for some brain teasers or simple maths questions, my advice would be to not panic and overthink (like I did), the answer may actually be in the question itself.
I then received an email inviting me to the AC the next day (the AC was two weeks after the telephone interview). It started at 12pm and ended at 4pm, consisted of two interviews and a group exercise. Both were motivational, slightly technical and competency again. They have your CV in front of them and may go through it with you. Have some articles in your mind and know what Treasury Services is, they will definitely ask you this. Prepare for some brain teasers and maths questions again, I personally was only asked one but some people in my group were asked 4+. My tip would be to always show passion, they can read you like a book and will end the interview quickly if they get bored. Finally, have questions prepared to ask both interviewers, they will be expecting this.
The group exercise was standard, 20 minutes to prepare a presentation, 5 minutes to present and 5 minutes for questions. My advice would to make sure you don't speak over people, always be open to different opinions and make sure everyone in your group is comfortable.
2 working days later, I received a phone call from HR giving me an offer.
Good luck and I hope this helps! I know that going online and reading glass door questions really helped me so I want to return the favour with my own experience.