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CONTRACTS AND AGREEMENTS - Brokerage Commissions (Details) - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Long Duration Contracts Assumptions By Product And Guarantee [Line Items] |  |  |
Brokerage commissions | $ 102,980 | $ 7,261 | $ 6,045
Brokerage commissions as a percentage of average daily net assets | 0.06% | 0.01% | 0.01%
Rebalancing Investments Transaction [Member] |  |  |
Long Duration Contracts Assumptions By Product And Guarantee [Line Items] |  |  |
Brokerage commissions | $ 35,522 | $ 6,695 | $ 4,961
Brokerage commissions as a percentage of average daily net assets | 34.49% | 92.20% | 82.07%
Trades Necessitated By Creation And Redemption Activity [Member] |  |  |
Long Duration Contracts Assumptions By Product And Guarantee [Line Items] |  |  |
Brokerage commissions | $ 67,458 | $ 566 | $ 1,084
Brokerage commissions as a percentage of average daily net assets | 65.51% | 7.80% | 17.93%

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