Michael Bay famously swore Transformers: Dark of the Moon would be his last in the series, leaving it to a new director to softly reboot the series with the fourth installment, only to return for last summer's Transformers: Age of Extinction, a sequel that dropped Mark Wahlberg into the exact same shenanigans that defined the three previous movies.
The master of Bayhem has indeed moved on; he's currently prepping the Benghazi film 13 Hours, yet the threat of another Baytastic Transformers still looms large.
See, Paramount is putting together a "writer's room" to farm ideas for a whole mess of Transformers multi-part sequels, spinoffs, and whatnot.
Bay, producer Lorenzo Di Bonaventura, and executive producer Steven Spielberg will organize this franchise brain trust, which will be overseen by Oscar-winning A Beautiful Mind screenwriter Akiva Goldsman, who also scripted Batman & Robin, Lost In Space, and Winter's Tale. Goldsman is currently in talks with the studio to take on this new role, which apparently won't involve any straightforward screenwriting, but will instead find him wrangling the various writers and ideas spawned in this creative incubator.
This is all coming together rapidly, because according to Deadline, Bay is eager to have a plan in place by the time he wraps on the sure-to-be subtle 13 Hours "so that the next Transformers pic can move forward quickly."
The wording there leaves whether or not Bay plans on actually directing or simply producing, but the implication is certainly there, especially since Age of Extinction proved Bay can slam out an Autobot adventure on a condensed schedule.
That the studio and toy-giant would want to take the interconnected universe approach is in no way surprising. Despite being objectively terrible, all four Transformers movies have been commercial juggernauts. Even as American audiences catch on, the series' popularity abroad, particular in the massive emerging Chinese market, has more than made up for it. Despite being by far the lowest grossing entry Stateside, Transformers: Age of Extinction was the second biggest in the franchise worldwide, earning more than $1 billion total thanks to a remarkable 78% of its global haul coming from international ticket sales.
As such, building a Transformers universe is a high priority at Paramount under Marc Evans, the new president of Paramount's Motion Picture Group. Evans is tasked with upping the studio's output, and a reliable way to do that to profitable effect is to give the world what it wants: more explosions, incomprehensible action sequences, misogyny, and weird racism. In short: more Transformers.