City hedge fund Toscafund, which last year acquired a number of mortgage books, is offering to write off up to 20% of UK mortgage holders’ borrowings if they remortgage with a new lender. The hedge fund uses a mortgage servicing company to administer its loans and borrowers who wish to remortgage away are being offered the opportunity to write off a large proportion of their debt if they refinance elsewhere. Chief investment officer of the Tosca Mod fund Charles Schrager says that for some borrowers it can be as much as 20%, but in most cases it is much less than this.