Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2012

Summary of Significant Accounting Policies [Abstract]

Transactions in call options

	Six Months Ended June 30, 2012						Year Ended December 31, 2011
	Number of Contracts			Premiums Received			Number of Contracts			Premiums Received
Outstanding, beginning of period		1,657		$	1,428,047			1,813		$	1,629,313
Options written		7,357			4,489,456			13,702			10,798,390
Options terminated in closing purchase transactions		(4,822	)		(2,775,250	)		(9,895	)		(8,022,605	)
Options expired		(2,528	)		(1,637,976	)		(3,963	)		(2,977,051	)
Outstanding, end of the period		1,664		$	1,504,277			1,657		$	1,428,047

Fund's fair value measurement

	June 30, 2012
	Level 1			Level 2			Level 3		Total
Short-Term Investments:
U.S. Government and Agency Obligations	$	—		$	149,832,352		$	—	$	149,832,352
Repurchase Agreements		—			13,600,973			—		13,600,973
Derivatives:
Futures Contracts*		2,788,740			—			—		2,788,740
Call Options Written**		(2,185,116	)		(152,116	)		—		(2,337,232	)
Total	$	603,624		$	163,281,209		$	—	$	163,884,833

	December 31, 2011
	Level 1			Level 2			Level 3		Total
Short-Term Investments:
U.S. Government and Agency Obligations	$	—		$	174,425,536		$	—	$	174,425,536
Repurchase Agreements		—			1,201,417			—		1,201,417
Derivatives:
Futures Contracts*		(4,921,830	)		—			—		(4,921,830	)
Call Options Written**		(548,427	)		(3,030	)		—		(551,457	)
Total	$	(5,470,257	)	$	175,623,923		$	—	$	170,153,666

* Represents net unrealized appreciation (depreciation) as reported in the Schedule of Investments.

** Refer to the Schedule of Investments for breakdown of Call Options Written classified as Level 2.