Strong position in the U.K. savings and mortgages market. Position as a "core" subsidiary of Banco Santander. Useful mix of retail and commercial business lines. Lower business diversification than its larger U.K. competitors. Reduced profitability. Risks of potential contagion from the wider group. Standard&Poor's Ratings Services' negative outlook on Santander UK PLC (SanUK) reflects the possibility of a negative rating action if, in our view, the weakening credit profile of Banco Santander S.A. ("Banco Santander" or "the parent"; BBB/Negative/A-2) jeopardizes SanUK's funding prospects or poses a significant threat to its confidence-sensitive deposit base. The negative outlook also captures the potential contagion risk from the wider group, which could affect SanUK's business position concerning decisions about how the business