ALLIANT ENERGY CORPORATION was formed as the result of a three-way merger involving WPLH, IES and IPC that was completed in April 1998. The primary first tier subsidiaries of Alliant Energy include: WP&L, IESU, IPC, Resources and Corporate Services. Among various other regulatory constraints, Alliant Energy is operating as a registered public utility holding company. Alliant Energy was incorporated in Wisconsin in 1981.

PRINCIPAL SUBSIDIARIES

The following is a brief description of the primary first-tier subsidiaries of Alliant Energy:

1. IES UTILITIES INC (IESU): IESU was incorporated in Iowa in 1925 as Iowa Railway and Light Corporation. IESU is a public utility doing business in the state of Iowa, and engaged principally in:

• the generation, transmission, distribution and sale of electric energy;
  
• the purchase, distribution, transportation and sale of natural gas; and

• the provision of steam services in selective markets.
  

2. WISCONSIN POWER & LIGHT COMPANY (WP&L): WP&L was incorporated in Wisconsin in 1917 as the Eastern Wisconsin Electric Company. WPL is a public utility engaged principally in:

• the generation, transmission, distribution and sale of electric energy;
  
• the purchase, distribution, transportation and sale of natural gas; and
  
• the provision of water services in selective markets.

Nearly all of WP&L's customers are located in south and central Wisconsin.

3. IPC: IPC was incorporated in 1925 under the laws of the State of Delaware. IPC is a public utility engaged principally in the generation, transmission, distribution and sale of electric energy and the purchase, distribution, transportation and sale of natural gas in the States of Iowa, Minnesota and Illinois.


4. RESOURCES: Resources was incorporated in 1988 in Wisconsin and the majority of Alliant Energy's non-regulated investments are organized under Resources. Resources' wholly-owned subsidiaries include ISCO, International, Investments, Transportation and Capital Square. These businesses include:

• domestic and international energy products and services businesses;
  
• industrial services, which includes environmental, engineering and transportation services;
  
• investments in affordable housing initiatives; and
  
• investments in various other strategic initiatives.

5. CORPORATE SERVICES: Corporate Services is a subsidiary formed to provide administrative services to Alliant Energy and its subsidiaries.


ELECTRIC UTILITY OPERATIONS

Alliant Energy's utility subsidiaries provides electricity to retail customers in Iowa, southern and central Wisconsin, northern and northwestern Illinois and southern Minnesota. Electric sales are seasonal to some extent with the annual peak normally occurring in the summer months.


GAS UTILITY OPERATIONS

Alliant Energy's utility subsidiaries provide retail natural gas service to customers in Iowa, southern and central Wisconsin, northern and northwestern Illinois and southern Minnesota. In providing gas commodity service to retail customers, Alliant Energy administers a diversified portfolio of transportation and storage contracts on behalf of each of the three utilities.


NON-REGULATED OPERATIONS

Resources is a holding company which is managed through five distinct platforms: Investments, International, Industrial Services, Cargill-Alliant and Mass Markets.


Investments Platform: Investments is a holding company whose primary subsidiaries include:

1. Heartland Properties, Inc., which is responsible for performing asset management and facilitating the development and financing of high quality, affordable housing in Alliant Energy's utility service territory.
   
2. Iowa Land and Building Company which is organized to pursue real estate and economic development activities in IESU's service territory.
   
3. Village Lakeshares Inc., which is a holding company for resort properties in Iowa.

International Platform: International is a holding company for Resources' international investments whose wholly-owned subsidiaries include:

1. Alliant International New Zealand Limited, which has equity investments in several New Zealand utility entities.
   
2. Alliant Energy Australia Pty Ltd., which has an equity investment in a holding company whose primary investments are infrastructure and utility companies in Australia.
   
3. Grandelight Holding Ltd., which has an equity investment in a company formed to develop investment opportunities in generation infrastructure projects in China.
   
4. Interstate Energy Corporation Pte Ltd., which has an equity investment in two individual facilities in China.
   
5. Alliant Energy Renewable Resources Ltd., which has been formed for the purpose of investing in international renewable resource projects.
   
6. Alliant Energy de Mexico L.L.C., which is organized to provide utility-related services to a resort community in Mexico.

Industrial Services Platform: ISCO is a holding company for Resources' industrial service companies whose primary wholly-owned subsidiaries include:

1. Industrial Energy Applications, Inc., which offers facilities-based energy services for customers, including standby generation, cogeneration, steam production and propane air systems.
   
2. Heartland Energy Group, Inc., which offers commodities-based energy services primarily related to supplying natural gas.
   
3. RMT, Inc., which is a Madison (WI) based environmental and engineering consulting company that specializes in solid and hazardous waste management, ground water quality protection, industrial design and hygiene engineering.