I'm looking at booking one of my regular itineraries tonight, for travel in ~3 weeks time (TUS-SCE). When I search on aa.com, each of the options shown include the words 'Corporate Rate' in green font. If I select an itinerary, the summary page says 'Includes corporate discount'.

I've never seen this before. Anyone have a clue as to what it is?

FWIW, I'm a run-of-the-mill PPro. I am travelling on business, but there's no way for AA to know that, and I always book via a personal CC.