...IDRs Based on Support: The IDRs and Support Rating of mBank reflect Fitch Ratings' opinion that there is an extremely high probability that the bank would be supported, if required, by its ultimate almost 70% shareholder, Commerzbank AG (A+/Negative/bbb). Fitch believes that mBank is a strategically important subsidiary of Commerzbank, and its support-driven Long-Term IDR is notched down once from that of the parent. The Negative Outlook on the Long-Term IDR reflects that on Commerzbank. Constrained Viability Rating: mBank's Viability Rating (VR) is constrained by material (albeit slowly declining) exposure to foreign-currency (FC) mortgages and substantial FC refinancing needs. The VR also reflects mBank's modest risk appetite, stable asset quality, fairly strong franchise, solid capitalisation and resilient performance. High Retail FC Exposure: The bank is vulnerable to Polish zloty weakening due to its large portfolio of FC residential mortgages (32% of gross loans at end-2014). However,...