Exhibit 21(a) Subsidiaries of Illinois Power Company State or Jurisdiction Name of Incorporation - ---- --------------------- Illinois Power Company Illinois IP Gas Supply Company Illinois Illinois Power Fuel Company (1) Illinois Illinois Power Capital, L.P. (2) Delaware Illinois Power Financing I Delaware Illinois Power Securitization Limited Liability company (3) Delaware Illinois Power Special Purpose Trust (4) Delaware (1) Illinois Power Company owned 50% of the common stock of Illinois Power Fuel Company. The Fuel Company was dissolved on February 23, 2000. (2) Illinois Power Company is the general partner in Illinois Power Capital, L.P., with a 3% equity ownership share. Illinois Power Capital is consolidated in the accounts of Illinois Power Company. (3) Illinois Power Company is the sole member of Illinois Power Securitization Limited Liability Company. (4) Illinois Power Securitization Limited Liability Company is the sole owner of the Illinois Power Special Purpose Trust.