Last month I posted the City of Philadelphia's list of largest private employers based on city wage tax data. The state of Pennsylvania has its own lists of major employers -- using state and federal unemployment insurance data -- and comes up with a significantly different list for the city.
It's not just that the state also tracks government employers (U.S. is #1 employer in Philadelphia, City is #2, School District #4, SEPTA #8, State #12). It looks like some big companies that are paying unemployment insurance for a lot of workers Philadelphia workers aren't paying similar levels of wage taxes.
Here's how the state ranks private, non-college, non-hospital employers in Philadelphia based on unemployment insurance records:

1. US Airways

2. Independence Blue Cross
3. AlliedBarton
4. Comcast Cablevision
5. Aramark Sports
6. Cardone Industries
7. Wells Fargo
8. PNC
9. Resources for Human Development Inc.
10. GlaxoSmithKline
11. Wal-Mart
12. Tenet Health System - St. Christopher's Hospital
13. Ace Ltd.
14. NBC (which is owned by Comcast, see also #4. Pa. shows ranks, not job totals. That makes it tough to aggregate companies with more than one reporting unit.)
15. Bayada Home Health Care
16. Cigna
17. Wawa
18. Aramark Management (see also #5)
19. Sunoco
20. The Phillies
21. Peco Energy

Compare that with the top private non-college non-hospital employers from the list compiled by the city from wage tax records
here (with link to data):
1) Independence Blue Cross
2) PNC
3) Comcast
4) Wells Fargo
5) Aramark
6) Ace Ltd.
7) GlaxoSmithKline
No USAir machinists, no AlliedBarton guards at the top of the city list. On the other hand, PNC and Ace rank higher on the wage-tax vs. the unemployment-insurance list.
UPDATE: Both USAir and AlliedBarton tell me they register suburban and traveling employees in Philadelphia for unemployment insurance purposes -- but don't levy wage tax on them when they're working outside city limits.