‘Transformers: Age of Extinction’: How big a hit is it?

On Monday morning, before the official numbers came in, “Transformers: Age of Extinction� had reached a benchmark — studio estimates had the film scoring a $100-million opening weekend. Exactly $100 million, in fact.

This is significant for at least two reasons: a) no other movie opening has managed to get to nine digits thus far this year; and b) “Transformers� has set that $100-million number as a standard for itself, having reached it with all but the first film when accounting for inflation

‎The first reason means that box office, otherwise down double digits so far this summer, is not as troubled as previously thought — for the moment, anyway. The second reason means that the Paramount franchise is not over, and in fact that the new start and direction, four movies in, didn’t turn out to be a detriment: Optimus Prime is alive and well and continues to turn his wheels.

Of course, those wheels may have lost a tiny bit of tread. The biggest opening weekend for a “Transformers� film came in 2009 with “Transformers: Revenge of the Fallen,� which after inflation took in $118 million, a nice chunk higher than this past weekend’s numbers. (The subsequent film, “Dark of the Moon,� was also higher, if by a hair, at $103 million, in 2011‎.) And it’s worth noting that “Revenge of the Fallen� did not have the advantage of higher 3-D ticket prices, as these last two films have.

Still, in a year when flat is the new up, Michael Bay’s new film is a success. International numbers, which offer less of a margin than domestic dollars do for studios, continue to gobble up an increasingly large chunk of “Transformers� (approaching 70% for the last film, with that ratio possibly repeated here.) But in a time when box office is down and fourquels in particular have gotten hammered (“Pirates of the Caribbean,� anyone?], “Transformers� is still kicking.

The tale is not yet fully told. Most films this summer have all gone off the cliff in the second weekend. The three biggest openings right behind “Transformers� — “Godzilla,� “X-Men: Days of Future Past� and “Amazing Spider-Man 2,� all with at least $90 million in their first weekend — dropped more than 60% in their second weekends.

These kinds of drops are why box office this summer was down nearly 15% coming into this past weekend. The two biggest grossers in 2014? “The Lego Movie� and “Captain America: Winter Soldier,� which opened in February and April, respectively. Box office overall is essentially flat this year.

“Transformers� has historically been able to hold up even after its opening; “Dark of the Moon,� for instance, dropped just 51% in its second weekend. With no other big-budget action-adventure opening over the July 4 weekend, “Transformers� should be able to match that number. But given how big the drops have been in 2014, all bets are off.

It’s not a stretch to say that as “Transformers� goes, so goes the summer movie business. And the summer movie business is going, if hardly with the same city-destroying firepower it once did.