The aim of this analysis is to provide insight and understanding of consumers who are approaching their interest only mortgage maturity and to establish a time horizon of all residential interest only mortgages due to reach the end of term over the next 30 years. The analysis in this report looks at the volume and value of residential interest only mortgages within the UK and examines concentrations by geography, demography and credit exposure of segments of the UK population. The remit of this analysis is to consider FCA regulated residential interest-only mortgages, and identify home owners who have exposure to maturity risk. Buy-to Let, Off-set and Lifetime mortgages are outside the scope of this analysis.  Through a combination of the FCA Product Sales Data (mortgage origination information) and Experian data on the monthly position of each mortgage, the current position of the interest only mortgage stock has been profiled. An algorithm has been developed to identify residential interest only mortgages ‘sold as’ such and those ‘converted’ to interest only terms or temporary basis)  some point in the account life. The algorithm uses original loan value, loan term, monthly payments, monthly balance changes and monthly arrears position to month-by-month repayment method, repayment, interest only and part and part. As the algorithm is based upon payment behavior if a mortgage is contractually on interest only terms but the consumer is over-paying this will be classified as repayment.