I'm thinking about running a game centered on city politics / AA business, with AAA runs being out of reach. I wanted a core theme the be "knowledge is power". What kinds of pay data can you think of that runners at this level could get, and who would want it?

Well anything really. The difference between AAA and AA could be a simple as a lack of funding for the brilliant ideas they have, to a particularly one sided approach to their company (We deliver the product, we don't make it. Or that sort of thing.)

AA corporations have limits. They're not every where. Not every one. AA companies are national powers, maybe with some limited international presence. Or maybe their a international player, but one that can't afford the big toys and glamorous lifestyle a AA company could. Maybe they can't afford to field a private army, or their telecommunications can't hold up to a serious breach.

With out more background I can't get more specific than that but I'm sure we can fill int he blanks if you'd like!

The real paydata is that the coffee fund is bigger than it should be.

Um, not quite. At least not according to the classification* in Corporate Download. AAs are also multinational, exterritorial megacorps. The key difference is that they don't have a seat on the corporate court. IIRC it's stated somewhere that the biggest AAs (Monobe for ex) are about as big as the smallest AAA. I'll give you that they won't be as diversified as the average AAA and may be absent from some geographical areas, but AAs are still far from a mom 'n pop shop or a garage start-up.

*Which is:
AAA: multinational, exterritorial megacorp with corporate court seat(s)
AA: multinational, exterritorial megacorp without a corporate court seat
A: multinational, non-exterritorial megacorp
Unrated: non-multinational corp

To the OP: Can you name the city/region where the campaign will take place? Knowing who the regional players will be would be quite helpful for answering your question.