In a new interview with Rolling Stone to promote his upcoming movie 13 Hours, Michael Bay revealed "I'm doing Transformers ... 5, is it?" Exactly when he signed on wasn't revealed but apparently pre-production is well under way as the interview partly occured during an interview with ILM as they went over effects for 13 Hours, TMNT 2 (a look at Krang and oddly making directing decisions on a film he didn't direct) and Transformers 5 where "They show Bay an underwater rendering of a crash-landed alien spaceship, then a new dump-truck Transformer with a cloak. Neither are up to snuff."
He has directed all five of the films and just like the last two times he also said "But it's time to move on. One more." Chances are Hasbro and Paramount backed up the money truck as he is rumored to have made close to $100 million for each of the last few films so can't really blame him for not wanting to say no to that. I also can't help but wonder if this time the action scenes are being driven by the script developed from the Transformers' Writing Room or if once again he comes up with the action scenes and the script is created to move the story from one action beat to the next as has been the case for the last three films.