Speculators care about obtaining exposure to risk. How they get that exposure if they can get in and out cheaply is secondary. If BitMEX is able to create a liquid market for Bitcoin quanto’ed derivatives, speculators will flock to them.
As I previously explained in “Why Quanto?”, in order for BitMEX to offer ETH/USD risk, we had to quanto into Bitcoin. This post will explore the concepts speculators care about.
For all the below examples we will use the following assumptions:Contract: ETHUSDMultiplier: 0.000001 XBT per 1 USDContracts: 10,000

The most important aspect to a speculator is the contract’s payoff function. Since we are speculating on the ETH/USD price, ideally the contract’s Bitcoin value should increase and decrease in a linear fashion with respect to the ETH/USD price.
I assume the speculator denominates their profit in Bitcoin (XBT) terms. Therefore the value of Bitcoin in USD terms at a particular ETH/USD price is irrelevant. Put simply, the speculator wants to use Bitcoin as a margin to earn more Bitcoin.
The above chart illustrates that at different ETHUSD values, the XBT value of the position changes linearly. That is exactly what the speculator desires.XBT Value = ETHUSD Price * Multiplier * # Contracts
How is the amount of Bitcoin margin calculated? The initial margin for the ETHUSD contract is 2%, or 50x leverage.Initial Margin (IM) = 2% * XBT ValueIf you enter the trade at an ETHUSD Price of $500, this is your initial margin requirement:IM = 2% * $500 * 0.000001 XBT * 10,000 = 0.10 XBTThe next important consideration is what is your liquidation price. That is determined by the maintenance margin. The maintenance margin for the ETHUSD contract is 1%. If the underlying ETH/USD spot price declines by 1%, you will be liquidated.

The PNL is denominated in Bitcoin. In Bitcoin terms, the PNL changes linearly with the ETHUSD price. If the contract goes up 1%, your Bitcoin PNL also goes up 1%. The chart above illustrates that.XBT PNL = (ETHUSD Exit Price - ETHUSD Entry Price) * Multiplier * # ContractsIn the above example, if the ETHUSD price moves from $500 to $600, this is the XBT PNL:XBT PNL = ($600 - $500) * 0.000001 XBT * 10,000 = 1 XBT
To get a certain amount of Bitcoin exposure requires a little math.
The following describes how to calculate how many contracts it takes to equal a desired Bitcoin notional.Contracts = XBT Notional / [ ETHUSD Price * Multiplier ]If you want 100 XBT of risk, how many contracts of ETHUSD must you trade:Contracts = 100 XBT / [ $500 * 0.000001 XBT ] = 200,000 ContractsThe quanto structure satisfies the desires of a Bitcoin-based speculator. The major components that speculators care about all vary linearly with respect to the ETH/USD price. The relative rich or cheapness of the contract vs. the underlying is not a major concern if the contract is liquid.
The factors that govern whether the contract will be at a premium or discount will be explored in the subsequent piece. These considerations heavily depend on how to hedge a quanto derivative from first principles. The hedging of the contract is where the non-linear effects matter.