Where is the headquarters of Philadelphia Insurance Companies located?

Accident Fund Insurance Company of America 27 Acuity Insurance 24 Aetna 30 American National Insurance Company 19 Amtrust Financial Services 25 Cincinnati Financial Corporation 27 Encompass Insurance Company 18 GAINSCO 13 Harvard Pilgrim Health Care 20 Health Care Service Corporation 25 Horace Mann Educators Corporation 27 Kemper Corporation 17 Merchants Insurance Group 10 progressive insurance company 33 Pure Insurance 19 Symetra 16 The Travelers Companies 18 TIAA 11 Westfield Insurance 12 White Mountains Insurance Group 23