We don't know they're not used as collateral, and it doesn't have to be in the lit markets where this happens. It could be in dark markets in Asia, having knock

We don't know they're not used as collateral, and it doesn't have to be in the lit markets where this happens. It could be in dark markets in Asia, having knock-on effects on demand or other investments in the real economy. There is also hedging, which automatically couples correlation into other markets.