Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2011

Summary of Significant Accounting Policies

Schedule of client commission arrangement

	2011			2010			2009
Client commissions	$	130.8		$	155.8		$	180.3
Prepaid research, gross	$	3.7		$	4.6		$	5.3
Allowance for prepaid research		(0.4	)		(0.4	)		(0.5	)
Prepaid research, net of allowance	$	3.3		$	4.2		$	4.8
Accrued research payable	$	50.7		$	41.6		$	39.0

Summary of weighted average assumptions used for grants

	2011			2010			2009
Dividend yield		0.0	%		0.0	%		0.0	%
Risk free interest rate		2.0	%		1.5	%		2.3	%
Expected volatility		40	%		44	%		49	%
Expected life (years)		4.76			4.00			4.00