Vast majority of large, publicly traded companies (at least in the US) only do pay determination (and associated raises) once per year. Promotions can definitely happen whenever but there may be a cycle associated with that as well.
You truly believe that such rules are written in stone? There's always exceptions if a need arise. Budgets of whole countries can be changed mid year but salary of some employee can't? :)
I worked in a large multinational bank with yearly promotion/raise process. When I was quitting, they managed to get a 50% raise in counter-offer.
Until you find a new position and they want to match it. Then you hate the paperwork within the day.
That's what calibration meetings are for. To determine who is worthy of promotion.