Exhibit 21(a)

ENERGY FUTURE HOLDINGS CORP.

SUBSIDIARY HIERARCHY

Effective December 31, 2011

	Jurisdiction
Energy Future Holdings Corp.	Texas
Energy Future Competitive Holdings Company	Texas
Texas Competitive Electric Holdings LLC	Delaware
TCEH Finance, Inc.	Delaware
Generation MT Company LLC	Delaware
EFH CG Holdings Company LP1	Texas
Luminant Holding Company LLC	Delaware
Luminant Energy Company LLC	Texas
Luminant ET Services Company	Texas
Luminant Energy Trading California Company	Texas
EFH CG Holdings Company LP2	Texas
EIP Holdings LLC3
Luminant Generation Company LLC	Texas
Nuclear Energy Future Holdings LLC	Delaware
Nuclear Energy Future Holdings II LLC	Delaware
Comanche Peak Nuclear Power Company LLC4	Delaware
Valley NG Power Company LLC	Texas
Luminant Renewables Company LLC	Texas
Fuelco LLC5	Delaware
EFH CG Holdings Company LP6	Texas
Generation SVC Company	Texas
Big Brown 3 Power Company LLC	Texas
Big Brown Power Company LLC	Texas
Collin Power Company LLC	Delaware
DeCordova Power Company LLC	Texas
Lake Creek 3 Power Company LLC	Texas
Martin Lake 4 Power Company LLC	Texas
Monticello 4 Power Company LLC	Texas
Morgan Creek 7 Power Company LLC	Texas
Oak Grove Management Company LLC	Delaware
Oak Grove Power Company LLC	Texas
Sandow Power Company LLC	Texas
Tradinghouse 3 & 4 Power Company LLC	Texas
Tradinghouse Power Company LLC	Texas
Valley Power Company LLC	Texas
Big Brown Lignite Company LLC	Texas
Luminant Big Brown Mining Company LLC	Texas
Luminant Mining Company LLC	Texas
Oak Grove Mining Company LLC	Texas
Luminant Mineral Development Company LLC	Texas
NCA Resources Development Company LLC	Texas
TXU Energy Retail Company LLC	Texas
TXU Retail Services Company	Delaware
EFH CG Holdings Company LP7	Texas
TXU SESCO Company LLC	Texas
TXU SESCO Energy Services Company	Texas
TXU Energy Solutions Company LLC	Texas
TXU SEM Company	Delaware
Pantellos Corporation8	Delaware

	Jurisdiction
Brighten Holdings LLC	Delaware
Brighten Energy LLC	Delaware
Energy Future Intermediate Holding Company LLC	Delaware
EFIH Finance Inc.	Delaware
Oncor Electric Delivery Holdings Company LLC	Delaware
Oncor Electric Delivery Company LLC9	Delaware
Oncor Management Investment LLC10	Delaware
Oncor Electric Delivery Transition Bond Company LLC	Delaware
Oncor Electric Delivery Administration Corp.	Texas
EFH CG Holdings Company LP11	Texas
Oncor License Holdings Company LLC	Texas
Oncor Communications Holdings Company LLC	Delaware
EFH Renewables Company LLC	Delaware
EFH Corporate Services Company	Texas
EFH CG Management Company LLC	Texas
EFH CG Holdings Company LP12	Texas
Generation Development Company LLC	Delaware
NCA Development Company LLC	Texas
EFH Properties Company	Texas
Basic Resources Inc.	Texas
TXU Receivables Company	Delaware
EFH Vermont Insurance Company	Vermont
LSGT Gas Company LLC	Texas
LSGT SACROC, Inc.	Texas
Humphreys & Glasgow Limited	United Kingdom
EEC Holdings, Inc	Nevada
EECI, Inc.	Nevada
Ebasco Services of Canada, Ltd	Canada
EFH CG Holdings Company LP13	Texas
EFH Australia (No. 2) Holdings Company	Delaware
EFH FS Holdings Company	Delaware
TXU Europe Limited	United Kingdom
TXU Europe CP Inc	Delaware
TXU Eastern Finance (A) Ltd	United Kingdom
TXU Eastern Finance (B) Ltd	United Kingdom
TXU Eastern Funding Company14	United Kingdom
EFH Finance (No. 2) Holdings Company	Delaware
TXU Finance (No. 2) Limited15	United Kingdom

¹  0.3% ownership interest

²  22% ownership interest

³  20% (2.5M) membership interest owned by Luminant Energy Company LLC

⁴  88% ownership interest

⁵  33.34% ownership interest

⁶  2.4% ownership interest

⁷  28.4% ownership interest

⁸  5.389% owned by TXU Energy Solutions Company LLC

⁹  80.033% ownership interest

¹⁰ Oncor Management Investment LLC owns 0.217% of Oncor Electric Delivery Company LLC. Regarding the ownership of Oncor Management Investment LLC, Oncor Electric Delivery Company LLC owns 100% of the Class A membership interests. Certain management employees of Oncor Electric Delivery Company LLC own 100% of the Class B membership interests.

¹¹ 19.5% ownership interest

¹² 21.5% ownership interest

¹³ 5.9% ownership interest

¹⁴ 50% owned by TXU Eastern Finance (A) Ltd and 50% owned by TXU Eastern Finance (B) Ltd

¹⁵ 10% owned by EFH Finance (No. 2) Holdings Company and 90% owned by TXU Europe Limited