Before revision:  Initial margin funding charge enters the PDE's delta term as a cost, irrespective of being a long or short position, effectively a tax that cannot be transferred between two clearing members, or a bid-ask spread a market maker charges uncollateralized clients or fellow financial counterparties .
After revision:  Initial margin funding charge enters the PDE's delta term as a cost, irrespective of being a long or short position, effectively a tax that cannot be transferred between two clearing members, or a bid-ask spread to transfer its funding cost .