AT&T Inc.(formerly SBC Communications, Inc.) is the parent company for BellSouth Corporation, Southwestern Bell Telephone Company, Pacific Telesis Group, Ameritech , and Southern New England Telephone. 1990 - 1991 Prior to 12/31/1991, BellSouth Corporation consisted of two separate operating companies: South Central Bell Telephone Company (SCTC) consisting of five study area jurisdictions: Alabama (SCAL), Kentucky (SCKY), Louisiana (SCLA),Mississippi (SCMS) and Tennessee (SCTN), and Southern Bell Telephone and Telegraph Company (SBTC) consisting of four study area jurisdictions: Florida(SBFL), Georgia (SBGA), North Carolina (SBNC), and South Carolina (SBSC).
Note: For years 1990 and 1991, the ARMIS data for the two operating companies have been combined under one COSA (BSTR) within the ARMIS system to allow comparison with later years. Thus, no individual data for COSAs SBTC and SCTC exists within the ARMIS system. 1992 - 1994 On 1/1/1992, South Central Bell and Southern Bell were merged, forming BellSouth Telecommunications, Inc. (BSTR), a corporation that is wholly-owned by BellSouth Corporation.
COSA |
Effect | SCTC | Discontinued | SBTC | Discontinued | BSTR | New COSA for entity that files as both an operating company and a holding company | 1995 BellSouth Telecommunications, Inc. had no changes during this period, except that on 1/1/1995, the names South Central Bell and Southern Bell were dropped and only BellSouth Telecommunications, Inc. was used. 1996 - 2005 BellSouth Telecommunications, Inc. had no changes during this period. 2006 BellSouth Telecommunications, Inc. merged with AT&T on December 29, 2006.
COSA |
Effect | BSTR | Brought under the control of AT&T Inc. | 2007 - 2009 BellSouth Telecommunications, Inc. had no changes during this period. 1990 - 1995 Prior to 1990, Southwestern Bell Telephone Company was both a holding company and operating company that consisted of five study area jurisdictions: Arkansas(SWAR), Kansas (SWKS), Missouri (SWMO), Oklahoma (SWOK), and Texas (SWTX). 1995 In 1995, a parent holding company named SBC Communications, Inc. was established, and Southwestern Bell Telephone Company's structural status as a holding company ceased. However, Southwestern Bell Telephone Company still existed as an operating company for its five study area jurisdictions.
COSA |
Effect | SWTR | Changed to an operating company only | 1996 - 2009 Southwestern Bell Telephone Company had no changes during this period.
1990 - 1996 Prior to 1990, Pacific Telesis Group was a holding company for two operating companies with one study area jurisdiction each: Pacific Bell, California(PTCA) and Nevada Bell, Nevada (PTNV). 1997 SBC Communications, Inc. acquired Pacific Telesis Group on 4/1/1997. SBC Communications, Inc., however, kept Pacific Telesis Group and its operating companies as separate reporting entities.
COSA |
Effect | PTTR | Brought under the control of SBC Communications, Inc. | 1998 - 2009 Pacific Telesis Group had no changes during this period.
1990 - 1998 Ameritech had no changes during this period. Prior to 1990, Ameritech was holding company for five operating companies with one study area jurisdiction for each: Illinois Bell (LBIL), Indiana Bell (NBIN), Michigan Bell (MBMI), Ohio Bell (OBOH) and Wisconsin Bell (WTWI). 1999 Ameritech was acquired by SBC Communications, Inc. on 10/8/1999. SBC Communications, however, kept Ameritech and its operating companies as separate reporting entity.
COSA |
Effect | AMTR | Brought under the control of SBC Communications | 2000 - 2009 Ameritech had no changes during this period.
Southern New England Telecommunications Corporation (SNCT) 1990 - 1997 Southern New England Telecommunications Corporation had no changes during this period. Southern New England Telecommunications Corporation is a holding and operating company with one study area jurisdiction. The Southern New England Telephone Company is the operating company with one study area jurisdiction: Connecticut. 1998 - 1999 SBC Communications, Inc. acquired Southern New England Telecommunications Corporation on 10/26/1998. SBC Communications, Inc., however, kept Southern New England Telecommunications Corporation as a separate reporting entity.
COSA |
Effect | SNCT | Brought under the control of SBC Communications, Inc. | 2000 - 2009 Southern New England Telecommunications Corporation had no changes during this period. | 
