https://www.npr.org/sections/money/2016/08/26/491342091/plan...
They traced the path of their barrel from purchase, to production, to refining, to the sale of the various hydrocarbon products.
It's a great listen.
This is why in rare occasions the price of a thing goes negative because trading in that thing you are contractually obligated to take delivery and people trying to unload that obligation sometimes can't find buyers until they are paid to take delivery. It happens when nobody really wants to buy a thing and there is no capacity left to store or ship. When you buy a futures contract and you don't want delivery you have to sell it to close your position, and rarely you have to give people large sums of money so you can close.
Suppose my actual oil futures go from $800k to $900k, the ideal ETF is trying to ensure that $800k also turns into $900k just as if its investors were in actual oil futures. But these aren't futures and don't result in delivery - so critically when real oil futures blow up and that $900k turns into -$1M because the global economy had a heart attack the ETF cannot be worth -$1M as it's just paper and I don't have to pay you one cent.
For the ETFs this means a negative exposure for the operator - they're eating unlimited downside but can't pass that on to their customers, and for a blip like 2020 that's survivable (if you're well capitalised) but longer term it would be fatal.
This, in many ways is a ridiculous sentence which shows what is wrong with the futures market. Futures are contracts for the supply of commodities. All futures should be settled by the actual commodity! That we have got to a situation where the vast majority of futures contracts are just 2nd order bets on the price of thing rather than delivery of the thing is non optimal.
Futures, specifically, are useful for implicitly borrowing commodities to control inventory levels across time. An airline needs continuous access to jet fuel, so to be safe, they buy more jet fuel than they need in the cash market. But they don't want to pay for owning all this jet fuel, so they simultaneously sell it off in the futures market. Thus, they have created a loan of jet fuel, making sure they have spare fuel available when they need it without outright having to own it.
In order to have a loan, one needs a speculator willing to buy the credit risk. More speculators usually leads to more liquidity and more accurate deals on loans. There's nothing wrong with this at all.
See The Economic Function of Futures Markets by Williams (1986) if you are curious.
It's not at all uncommon to trade a tanker load of oil, and this may result in the tanker being re-directed mid-trip, or being anchored somewhere for a while. Those are normal shipping events. (Yes, there are parking spaces for oil tankers. Here are the ones in the San Francisco Bay.[1])
I have read of an oil trader who bought a trainload of railroad tank cars of oil as a similar deal. That was a bigger hassle, because finding and paying for a storage track to park the tank cars became his problem. There is a market in railroad siding for storage, but there are not that many available spaces. Most of them are in Outer Nowhere, someplace where there used to be something that needed track but no longer does.[2] Managing this tied up a lot of high-priced broker time. Supposedly worked out OK, but nobody wanted to do it again.
[1] https://www.sfmx.org/wp-content/uploads/2017/01/Anchorage-9-...
"F*K HIM!!!!"