I'm not sure where you saw splitting the loss between investment and ponzi. usually in a ponzi every $ sent is lost immediately and there are no real trades despite what confirms might show. if you want to do the best for her, then use the services of a tax attorney or CPA familiar with Ponzi reporting. costly but then there is someone that can represent her and if needed defend the position taken if they split the loss. The burden of proof that part of the loss was from trading is on the taxpayer not the iRS
