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FINANCIAL HIGHLIGHTS - Per share performance data and other supplemental financial data (Details) - $ / shares | 3 Months Ended
--- | ---
Mar. 31, 2022 | Mar. 31, 2021
Per Share Operating Performance: |  |  |
Net asset value, beginning of year |  | $ 12.39 | $ 9.20
Total income (loss) |  | 7.34 | 0.44
Total expenses |  | (0.04) | (0.03)
Net increase (decrease) in net asset value |  | 7.30 | 0.41
Net asset value, end of period |  | $ 19.69 | $ 9.61
Total Return |  | 58.92% | 4.46%
Ratios to Average Net Assets |  |  |
Total income (loss) |  | 58.44% | 8.46%
Management fees | [1] | 0.60% | 0.60%
Total expenses excluding management fees | [1] | 0.42% | 0.57%
Net income (loss) |  | 58.19% | 8.18%
[1] | # Annualized.

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