Why is the Unit Production Manager often first in film credits?

When you're expecting to see the director's name...

The beginning of Guardians of the Galaxy's closing credits

Hollywood has fierce traditions and even fiercer unions. As such, the format of its crediting system is pretty uniform.

You might be wondering why films sometimes conclude, with a musical crescendo, to reveal the name of the Unit Production Manager(s) of all people, before the rest of the names of cast and crew involved roll up the screen.

Many/most films only have closing credits, which will start with the director/writer-director credit, but some use both opening and closing credits, often for stylistic reasons (like the James Bond films). In this case, the crew is separated into above-the-line and below-the-line categories, which originate in the top sheet of a budget for a motion picture and separate fixed cost roles from variable cost roles. For example, a director, producer or even screenwriter (regardless of whether a scene from their script gets cut) will be paid a fixed fee for their work, whereas a gaffer or set designer’s work is more flexible as a scene being cut may mean that a particular set simply doesn’t need to be built.

Of the below-the-line crew, the first and second assistant directors are always high up the credits list, but it is usually the unit production manager who gets the honour of having their name up in lights first after the film climaxes.