5. What is the max loss for DBOE Option Sellers?

DBOE Option is risk-bounded as mathematically DBOE Call is a difference of two regular Calls having the same underlying, expiry but different strikes and DBOE Put is a difference of two regular Puts having the same underlying, expiry but different strikes.

Therefore, max loss for DBOE Option sellers are their collaterals. Collateral deposited is calculated basing on the difference of the two strikes times quantity.