You can open a short futures position in /XBT (1 btc contract) or /BTC (5 btc contract), but that is obviously not safe, and the margin requirements to even ent

You can open a short futures position in /XBT (1 btc contract) or /BTC (5 btc contract), but that is obviously not safe, and the margin requirements to even enter are insanely large. And they don’t offer options, so there really is no way to limit your risk.