The following is a summary of receivables from and payables to brokers, dealers and clearing organizations (dollars in thousands):

	Receivables from						Payables to

	2011			2010			2011		2010
Broker-dealers	$	205,975		$	246,560		$	370,146	$	403,432
Clearing organizations		2,365			413			14,945		108,526
Securities borrowed		663,293			618,662			—		—
Securities loaned		—			—			694,682		628,000
Allowance for doubtful accounts		(318	)		(384	)		—		—

Total	$	871,315		$	865,251		$	1,079,773	$	1,139,958

The following is a summary of receivables from and payables to customers (dollars in thousands):

	Receivables from						Payables to

	2011			2010			2011		2010
Customers	$	473,852		$	607,286		$	207,738	$	272,027
Allowance for doubtful accounts		(1,343	)		(1,030	)		—		—

Total	$	472,509		$	606,256		$	207,738	$	272,027

The Company maintains an allowance for doubtful accounts based upon estimated collectability of receivables. The allowance was increased by $0.2 million in 2011 and 2010 after a decrease of $1.7 million in 2009. Total write-offs against the allowance of $0.1 million, $0.1 million and $0.3 million were recorded during 2011, 2010 and 2009, respectively.

As of December 31, 2011, securities borrowed as part of the Company's matched book operations with a fair value of $642.7 million were delivered for securities loaned. The gross amounts of interest earned on cash provided to counterparties as collateral for securities borrowed, and interest incurred on cash received from counterparties as collateral for securities loaned, and the resulting net amount included in other revenue on the Consolidated Statements of Operations for 2011 and 2010 were as follows (dollars in thousands):

	2011			2010

Interest earned	$	19,130		$	4,994
Interest incurred		(14,646	)		(3,540	)

Net	$	4,484		$	1,454