Note 10 - Investment Valuation (Tables)

3 Months Ended

Mar. 31, 2020

Notes Tables

Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Table Text Block]

	Level 1			Level 2		Level 3		Total
March 31, 2020
Futures contracts(a)	$	(125,957,813	)	$	—	$	—	$	(125,957,813	)
U.S. Treasury bills		—			491,322,390				491,322,390
December 31, 2019
Futures contracts(a)	$	19,634,651		$	—	$	—	$	19,634,651
U.S. Treasury bills		—			750,519,365		—		750,519,365