Does anyone know the method IB uses to distribute option assignments between accounts? I was suprised to find 32/50 at-the-money nakid puts were assigned in one account and 0/25 were assigned in another account over the weekend. I couldn't find the IB option assignment method by doing a search of the IB website or in the customer agreement (where Etrade has it). So I'm still looking for the IB policy and any help would be appreciated...
