...Support Drives IDRs: Qatar International Islamic Bank's (QIIB) Issuer Default Ratings (IDRs) are driven by an extremely high probability of support from the Qatari authorities, if needed. This reflects Qatar's strong ability to support its banks, as indicated by its rating, combined with Fitch Ratings' belief that there would be a strong willingness to do so. Narrow Franchise Constrains VR: QIIB's Viability Rating (VR) is constrained by its limited franchise (3.4% market share by total assets at end-2017) in the Qatari banking sector. However, QIIB enjoys higher shares in the Islamic banking segment in Qatar (13% at end- 2017), in particular in retail. The bank is looking to expand its franchise internationally and recently established a bank in Morocco. High Financing Concentrations: The impaired financing ratio fell to 1.4% at end-1Q18 following rapid financing growth and large write-offs, which compares reasonably with peers'. However, QIIB's financing book is concentrated by borrower,...