5 to 6 rounds of interviews. Initial recruiter screening, then two 30 minute interviews with members of the team (or people in roles that work close with the team you are trying to join), then a hiring manager interview, then at least two more 30 minute interviews with more senior members of the team (or peers of the hiring manager). Most of the conversations went well and were pretty standard interviews. The only interview that was not a pleasant experience was the final (5th or 6th round) with an executive who basically just began rapidly firing risk management questions at me that sounded like questions you would answer in a CISSP/CISM type examine. Given the seniority of the position this interview was for, the questions and interview style seemed odd. It was also a complete change from the 4 or 5 interviews that preceded this one. One benefit of so many interviews was that I at least got a very clear picture of the team and organization structure. That last round of interview definitely left a bad impression though.
Other thoughts on the overall process: From an HR technology and candidate experience perspective, there is definitely a lot of room for improvement. Interview scheduling is still being done in a very manual way even though most leading companies these days have implemented more modern scheduling workflows. They also don't notify you if you don't get the job (I verified this with others who were also rejected for other roles at MassMutual). The closest you get to being informed of their decision is that several weeks after your last communication with them, you can log into the candidate portal and see your application status has been changed to "No longer considered". Similar to the point of interview scheduling, this is a pretty simple problem to resolve with the technology that is available (and affordable) today. At the very least you can send rejected candidates a quick email informing them of that decision, especially after they have invested so much time in the interview process.