...Standalone Profile Drives IDRs: Turkiye Is Bankasi A.S.'s (Isbank) Issuer Default Ratings (IDRs) are driven by its Viability Rating (VR). The VR reflects the challenging operating environment and significant foreign-currency (FC) debt, as well as the bank's broad and diversified franchise, and reasonable financial metrics. Heightened Risks: Isbank's credit profile is sensitive to broader macroeconomic risks, including a volatile currency and frequent interest-rate movements. The Rating Watch Negative (RWN) on Isbank's VR reflects risks to the bank's performance, asset quality, capitalisation and funding and liquidity profile following a recent period of increased market volatility in the Turkish operating environment. Strong Franchise: Isbank is the largest privately owned bank in Turkey, with a 12% share of assets at end-2017. Fitch Ratings expects the bank to preserve its franchise and broad geographical coverage, which contribute to its healthy margins and diversified income sources,...