Exhibit A
Nicor
Significant Subsidiary Test
12/31/2004
(dollars in thousands)
Investment and Advances
Triton
Investment in Triton at 12/31/04					$	87,087
Advances to Triton at 12/31/04						-
					$	87,087
Nicor's consolidated total assets @ 12/31/04					$	3,975,229
Percentage						2.2%
Threshold indicating subsidiary is significant						10.0%
Total Assets
		Assets @ 9/30/04	Ownership			Nicor's
Triton		After Interco Elims		Percentage		Share
1997 Tranche	$	61,741		24%	$	14,818
1998 Tranche		185,452		18%		33,381
1999 Tranche		149,897		18%		26,981
2000 Tranche		245,795		10%		24,580
2001 Tranche		176,469		15%		26,470
2002 Tranche		142,914		20%		28,583
2003 Tranche		200,112		19%		37,521
					$	192,334
Nicor's consolidated total assets @ 12/31/04					$	3,975,229
Percentage						4.8%
Threshold indicating subsidiary is significant						10.0%
Equity in Income Before Income Taxes(before extraordinary items or cumulative effect of accounting changes)
Triton
IBIT for 12 months ended 9/30/04					$	113,744
X portion allocated to Nicor						5.465%
Nicor's share of Triton IBIT for 12 months ended 9/30/04						6,216
Less 4Q 2003 estimate plus 4Q 2004 estimate						275
Nicor's share of Triton IBIT recorded in 2004					$	6,491
Nicor's 2004 consolidated IBIT					$	105,341
Add back: Equity losses recorded by Nicor in 2004						2,413
Nicor's 2004 consolidated IBIT used for this analysis					$	107,754
Percentage						6.0%
Threshold indicating subsidiary is significant						10.0%
CONCLUSION:
Triton is not considered a significant subsidiary accounted for by the equity method because none of the conditions listed in Rule 1-02 of Regulation S-X are met.