[tobessebot]

https://www.sciencedirect.com/science/article/abs/pii/S03784...

https://www.tandfonline.com/doi/abs/10.1080/0960310011008808...

Futures markets do increase spot market efficiency.

[batterseapower]

These are financial futures. For some evidence that the presence of futures stabilises spot commodity prices see e.g. http://qed.econ.queensu.ca/CNEH/2005/papers/futures_CNEH_030...

[tobessebot]

Thanks for the addition!