This study investigates project financiers’ perspectives on the bankability of completion risk in Private Finance Initiatives and Public Private Partnerships (PFI/PPP) mega projects. Using a mixed methodology approach, focus group discussions with financier stakeholders in UK’s PFI/PPP industry were used to identify 23 criteria relevant for evaluating completion risk in funding applications. These criteria were put in a questionnaire survey to wider audiences of financiers of PFI/PPP projects in the UK. Series of statistical tests were performed, including Reliability Analysis, Kruskal-Wallis Non-Parametric Test, Descriptive Statistics, Principal Rank Agreement Factor (PRAF) and Regressions Analysis. After identifying 21 reliable criteria influencing the bankability of completion risk, the general agreement of three major financier stakeholders (Senior Lenders, Equity Financiers and Infrastructure Financiers) on all the criteria were examined through Kruskal-Wallis test and PRAF. A regression model, constructed and validated with input from another team of expert financiers, revealed five key criteria influencing the bankability of completion risk in PPP mega projects. These include (1) Construction contractor with years of experience of successful completion of mega projects, (2) Construction Contractor’s financial strength, (3) Existence of Tried-and Test Technology for the construction of project, (4) Availability of Independent Technical Consultant (ITC) and (5) Existence of Fixed Price Turn Key (FPTK) construction contract. The research findings will provide PFI/PPP contractors and clients with valuable strategies for satisfying financiers’ requirements in delivering large-scale Infrastructure PPP projects