"Delivery shall be made free-on-board ("F.O.B.") at any pipeline or storage facility in Cushing, Oklahoma with pipeline access to Enterprise, Cushing storage or Enbridge, Cushing storage."
Sure, but a majority of trading was done on CME futures. In either case, you still ran into the issue of negative prices. USO only recently started explicitly stating that they would also potentially invest in ICE futures alongside CME futures.
"Delivery shall be made free-on-board ("F.O.B.") at any pipeline or storage facility in Cushing, Oklahoma with pipeline access to Enterprise, Cushing storage or Enbridge, Cushing storage."
Source: https://www.cmegroup.com/trading/energy/crude-oil/light-swee...