...Viability-Driven IDRs: United Bulgarian Bank's (UBB) IDRs are driven by its standalone financial strength expressed by its Viability Rating (VR). The VR reflects UBB's weak asset quality, marked by high non-performing loans (NPLs) and concentration in construction and real estate sectors, but decent loss absorption capacity. Broadly stable deposit based funding and comfortable liquidity underpin UBB's credit profile. The Stable Outlook on the Long-Term IDR reflects asset quality stabilisation and return to profitability, which reduce capital pressures. The Long-Term IDR is one notch above that of UBB's parent, National Bank of Greece (NBG; B-/Stable/b-/5). This reflects Fitch Ratings' view of only limited contagion risk to UBB from NBG. This is primarily based on no significant reliance on parental funding and only limited credit exposure to NBG and related entities. Weak Asset Quality: Asset quality is the key factor constraining UBB's ratings. The NPL stock is high and credit risks are...