CBOT Margin Changes - Silver

Effective Close of Business April 17, 2006

Changes to Margins on CBOT Futures

	From	To
	Initial/Maintenance/Hedge	Initial/Maintenance/Hedge
Silver	$2,430/$1,800/$1,800	$3,510/$2,600/$2,600
Mini-sized Silver	$486/$360/$360	$702/$520/$520
2 Year Treasury Notes	$405/$300/$300	$506/$375/$375

Changes to Inter-Commodity Spreads

CBOT Futures		From		To
Ratio	Spread	Spread Credit %	Initial/Maintenance/Hedge	Spread Credit %	Initial/Maintenance/Hedge
2:3	Corn vs. Oats	40%	$1,539/$1,140/$1,140	55%	$1,154/$855/$855
10:3	Mini-sized Corn vs. Oats	40%	$1,539/$1,140/$1,140	55%	$1,154/$855/$855
1:1	Soybeans vs. Soybean Meal	60%	$864/$640/$640	75%	$540/$540/$400
5:1	Mini-sized Soybeans vs. Soybean Meal	60%	$864/$640/$640	75%	$540/$540/$400
1:1	SA Soybeans vs. Soybean Meal	60%	$891/$660/$660	75%	$557/$413/$413
2:3	Soybean Meal vs. Soybean Oil	45%	$2,228/$1,650/$1,650	60%	$1,620/$1,200/$1,200
3:1	2 Year T-Note vs. Treasury Bonds	65%	$957/$709/$709	75%	$683/$506/$506

Changes to Inter-Exchange Spreads

CBOT Futures		From	To
Ratio	Spread	Spread Credit %	Spread Credit %
3:1	Mini-sized Dow Jones Industrial Average vs. S&P 500 Barra Value	90%	85%
3:2	Dow Jones Industrial Average vs. S&P 500 Barra Value	90%	85%
3:5	BIG Dow DJIA $25 vs. S&P 500 Barra Value	90%	85%
1:2	5 Yr Swap vs. 1-Month Libor	55%	65%
5:2	5 Yr Swap vs. 2 Yr Swap	70%	80%
2:1	5 Yr Swap vs. CME 5 Yr Swap	70%	80%
2:1	5 Yr Swap vs. CME 10 Yr Swap	70%	80%

Changes to Intra-Crop Year Spread Margin Add-On

	From	To
	Initial/Maintenance/Hedge	Initial/Maintenance/Hedge
Oats	$270/$200/$200	$371/$275/$275
Wheat	$68/$50/$50	$135/$100/$100
Mini-sized Wheat	$14/$10/$10	$27/$27/$20

Changes to Implied Volatility Scan Range

	From	To
Soybean Meal	5.0%	3.5%

In setting margins levels, the Chicago Board of Trade Margin Committee along with the CME Clearing House monitors current and historical price movements covering short-term, intermediate and longer-term data using statistical and parametric and non-parametric analysis. Futures maintenance margin levels are typically set to cover at least the maximum one-day price move on 95% to 99% of the days during these time periods.