Note 2 - Significant Accounting Policies - Summary of Investments at Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Sep. 30, 2025
Fair Value, Inputs, Level 1 [Member]
Investments, fair value	$ 29,618,787	$ 20,855,894
Fair Value, Inputs, Level 1 [Member] \| SPDR Gold Mini Shares Trust [Member]
Investments, fair value	29,618,787	20,855,894
Fair Value, Inputs, Level 2 [Member]
Investments, fair value	0	0
Fair Value, Inputs, Level 2 [Member] \| SPDR Gold Mini Shares Trust [Member]
Investments, fair value	0	0
Fair Value, Inputs, Level 3 [Member]
Investments, fair value	0	0
Fair Value, Inputs, Level 3 [Member] \| SPDR Gold Mini Shares Trust [Member]
Investments, fair value	0	0
Investment in Gold [Member] \| Fair Value, Inputs, Level 1 [Member]
Investments, fair value	29,618,787	20,855,894
Investment in Gold [Member] \| Fair Value, Inputs, Level 1 [Member] \| SPDR Gold Mini Shares Trust [Member]
Investments, fair value	29,618,787	20,855,894
Investment in Gold [Member] \| Fair Value, Inputs, Level 2 [Member]
Investments, fair value	0	0
Investment in Gold [Member] \| Fair Value, Inputs, Level 2 [Member] \| SPDR Gold Mini Shares Trust [Member]
Investments, fair value	0	0
Investment in Gold [Member] \| Fair Value, Inputs, Level 3 [Member]
Investments, fair value	0	0
Investment in Gold [Member] \| Fair Value, Inputs, Level 3 [Member] \| SPDR Gold Mini Shares Trust [Member]
Investments, fair value	$ 0	$ 0