Note 9 - Investing in Index Futures - Effect of the Futures Contracts, by Risk Exposure Category, on the Statements of Operations (Details) - USD ($) |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2026 |
Sep. 30, 2025 |
Sep. 30, 2026 |
Sep. 30, 2025 |
|
| Net realized gain (loss) from futures contracts | $ 114,685,407 | $ 17,956,102 | $ 373,712,545 | $ 48,119,207 |
| Net change in unrealized appreciation (depreciation) on futures contracts | 84,736,873 | 11,839,522 | 3,820,278 | (25,642,257) |
| Commodity Contract [Member] | ||||
| Net realized gain (loss) from futures contracts | 114,685,407 | 17,956,102 | 373,712,545 | 48,119,207 |
| Net change in unrealized appreciation (depreciation) on futures contracts | $ 84,736,873 | $ 11,839,522 | $ 3,820,278 | $ (25,642,257) |