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Condensed Schedule of Investments	Jun. 30, 2018 USD ($)
Value/ Unrealized Gain (Loss) on Open Commodity Contracts	$ (5,130,125)
Open Futures Contracts - Long [Member] | United States [Member]
Notional Amount	$ 341,477,845	[1]
Number of Contracts	20,653	[1]
Value/ Unrealized Gain (Loss) on Open Commodity Contracts	$ (5,130,125)	[1]
% of Partners' Capital	(1.53%)	[1]
Open Futures Contracts - Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG August 2018 contracts, expiring July 2018
Notional Amount	$ 250,901,940
Number of Contracts	8,453
Value/ Unrealized Gain (Loss) on Open Commodity Contracts	$ (3,736,220)
% of Partners' Capital	(1.11%)
Open Futures Contracts - Long [Member] | United States [Member] | ICE Natural Gas Futures LD1 H August 2018 contracts, expiring August 2018
Notional Amount	$ 90,575,905
Number of Contracts	12,200
Value/ Unrealized Gain (Loss) on Open Commodity Contracts	$ (1,393,905)
% of Partners' Capital	(0.42%)
Cash Equivalents [Member]
Market Value	$ 311,184,062
% of Partners' Capital	92.52%
Cash Equivalents [Member] | United States Treasury Obligations [Member]
Market Value	$ 253,184,062
% of Partners' Capital	75.28%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 1.56%, 7/05/2018 [Member]
Principal Amount	$ 10,000,000
Market Value	$ 9,998,278
% of Partners' Capital	2.97%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 1.56%, 7/12/2018 [Member]
Principal Amount	$ 10,000,000
Market Value	$ 9,995,264
% of Partners' Capital	2.97%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 1.77%, 8/16/2018 [Member]
Principal Amount	$ 5,000,000
Market Value	$ 4,988,787
% of Partners' Capital	1.48%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 1.82%, 8/23/2018 [Member]
Principal Amount	$ 5,000,000
Market Value	$ 4,986,750
% of Partners' Capital	1.48%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 1.85%, 9/06/2018 [Member]
Principal Amount	$ 5,000,000
Market Value	$ 4,982,971
% of Partners' Capital	1.48%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 1.90%, 9/27/2018 [Member]
Principal Amount	$ 10,000,000
Market Value	$ 9,954,106
% of Partners' Capital	2.96%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 1.90%, 10/11/2018 [Member]
Principal Amount	$ 25,000,000
Market Value	$ 24,866,833
% of Partners' Capital	7.40%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 1.97%, 10/18/2018 [Member]
Principal Amount	$ 5,000,000
Market Value	$ 4,970,479
% of Partners' Capital	1.48%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 2.00%, 10/25/2018 [Member]
Principal Amount	$ 10,000,000
Market Value	$ 9,936,200
% of Partners' Capital	2.96%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 2.00%, 11/01/2018 [Member]
Principal Amount	$ 10,000,000
Market Value	$ 9,932,350
% of Partners' Capital	2.95%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 2.03%, 11/08/2018 [Member]
Principal Amount	$ 20,000,000
Market Value	$ 19,855,194
% of Partners' Capital	5.90%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 2.05%, 11/15/2018 [Member]
Principal Amount	$ 15,000,000
Market Value	$ 14,884,121
% of Partners' Capital	4.43%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 2.07%, 11/23/2018 [Member]
Principal Amount	$ 15,000,000
Market Value	$ 14,876,146
% of Partners' Capital	4.42%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 2.05%, 11/29/2018 [Member]
Principal Amount	$ 15,000,000
Market Value	$ 14,872,594
% of Partners' Capital	4.42%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 2.09%, 12/06/2018 [Member]
Principal Amount	$ 20,000,000
Market Value	$ 19,818,300
% of Partners' Capital	5.89%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 2.06%, 12/13/2018 [Member]
Principal Amount	$ 25,000,000
Market Value	$ 24,766,250
% of Partners' Capital	7.37%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 2.09%, 12/20/2018 [Member]
Principal Amount	$ 30,000,000
Market Value	$ 29,703,300
% of Partners' Capital	8.83%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 2.07%, 12/27/2018 [Member]
Principal Amount	$ 20,000,000
Market Value	$ 19,796,139
% of Partners' Capital	5.89%
Cash Equivalents [Member] | United States [Member] | Money Market Funds [Member]
Market Value	$ 58,000,000
% of Partners' Capital	17.24%
Cash Equivalents [Member] | United States [Member] | Money Market Funds [Member] | Fidelity Investments Money Market Funds - Government Portfolio [Member]
Principal Amount	$ 3,000,000
Market Value	$ 3,000,000
% of Partners' Capital	0.89%
Cash Equivalents [Member] | United States [Member] | Money Market Funds [Member] | Goldman Sachs Financial Square Funds - Government Fund - Class FS [Member]
Principal Amount	$ 50,000,000
Market Value	$ 50,000,000
% of Partners' Capital	14.86%
Cash Equivalents [Member] | United States [Member] | Money Market Funds [Member] | Morgan Stanley Institutional Liquidity Funds - Government Portfolio [Member]
Principal Amount	$ 5,000,000
Market Value	$ 5,000,000
% of Partners' Capital	1.49%
[1] Collateral amounted to $30,787,364 on open futures contracts.

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