Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2015

Accounting Policies [Abstract]

Summary of the Tiered Valuation Input Levels

The following is a summary of the tiered valuation input levels as of June 30, 2015:

	Level 1			Level 2		Level 3		Total
United States Treasury Obligations	$	—		$	217,001,291	$	—	$	217,001,291
Commodity Futures Contracts(a)	$	(23,171,081	)	$	—	$	—	$	(23,171,081	)

(a) Unrealized appreciation (depreciation).

The following is a summary of the tiered valuation input levels as of December 31, 2014:

	Level 1		Level 2			Level 3		Total
United States Treasury Obligations	$	236,994,724	$	—		$	—	$	236,994,724
Commodity Futures Contracts(a)	$	—	$	(13,474,175	)	$	—	$	(13,474,175	)

(a) Unrealized appreciation (depreciation).

Fair Value of Derivative Instruments and Effect of Derivative Instruments on Statements of Income and Expenses

The Fair Value of Derivative Instruments is as follows:

	June 30, 2015					December 31, 2014
Risk Exposure/Derivative Type	Assets		Liabilities			Assets		Liabilities
Commodity risk
Commodity Futures Contracts(a)	$	—	$	(23,171,081	)	$	—	$	(13,474,175	)

(a) Values are disclosed on the June 30, 2015 and December 31, 2014 Statement of Financial Condition under Net Unrealized appreciation (depreciation) on commodity futures contracts.

The Effect of Derivative Instruments on the Statements of Income and Expenses is as follows:

Risk Exposure/Derivative Type	Location of Gain or (Loss) on Derivatives Recognized in Income	For the Three Months Ended June 30, 2015			For the Three Months Ended June 30, 2014
Commodity risk
Commodity Futures Contracts	Net Realized Gain (Loss)	$	(2,095,499	)	$	(2,041,000	)
	Net Change in Unrealized Gain (Loss)		(14,673,468	)		22,767,125
Total		$	(16,768,967	)	$	20,726,125
Risk Exposure/Derivative Type	Location of Gain or (Loss) on Derivatives Recognized in Income	For the Six Months Ended June 30, 2015			For the Six Months Ended June 30, 2014
Commodity risk
Commodity Futures Contracts	Net Realized Gain (Loss)	$	(16,422,029	)	$	(14,709,256	)
	Net Change in Unrealized Gain (Loss)		(9,696,906	)		19,954,375
Total		$	(26,118,935	)	$	5,245,119

Summary of Average Monthly Notional Value of Future Contracts Outstanding

The table below summarizes the average monthly notional value of commodity futures contracts outstanding during the period:

	Commodity Futures Contracts				Commodity Futures Contracts
	For the Three Months Ended June 30,				For the Six Months Ended June 30,
	2015		2014		2015		2014
Average Notional Value	$	215,120,550	$	314,569,045	$	206,643,140	$	297,296,490

Summary of Gross and Net Amounts of Offsetting Liabilities

The following table presents derivative instruments that are either subject to an enforceable netting agreement or offset by collateral arrangements as of June 30, 2015, net by contract:

	Gross Amounts Recognized(a)			Gross Amounts Offset in the Statement of Financial Condition		Net Amounts Presented in the Statement of Financial Condition			Gross Amounts Not Offset in the Statement of Financial Condition
									Financial Instruments(b)		Cash  Collateral Pledged(b)		Net Amount
Liabilities
Commodity Futures Contracts	$	(23,171,081	)	$	—	$	(23,171,081	)	$	23,171,081	$	—	$	—

The following table presents derivative instruments that are either subject to an enforceable netting agreement or offset by collateral arrangements as of December 31, 2014 net by contract:

	Gross Amounts Recognized(a)			Gross Amounts Offset in the Statement of Financial Condition		Net Amounts Presented in the Statement of Financial Condition			Gross Amounts Not Offset in the Statement of Financial Condition
									Financial Instruments(b)		Cash  Collateral Pledged(b)		Net Amount
Liabilities
Commodity Futures Contracts	$	(13,474,175	)	$	—	$	(13,474,175	)	$	—	$	13,474,175	$	—

(a) Includes cumulative appreciation (depreciation) of futures contracts.

(b) As of June 30, 2015 and December 31, 2014, a portion of the Fund’s cash and US Treasury Obligations were required to be deposited as margin in support of the Fund’s futures positions as described in Note 3.