SAN FRANCISCO (S&P Global Ratings) Aug. 12, 2016--S&P Global Ratings assigned its 'AA' long-term rating to Portland, Ore.'s series 2016A first-lien sewer system revenue refunding bonds and its 'AA-' long-term rating to the city's series 2016B second-lien sewer system revenue refunding bonds. At the same time, we also affirmed our 'AA' long-term rating and underlying rating (SPUR) on the city's existing first-lien sewer system revenue bonds and our 'AA-' long-term rating and SPUR on the city's existing second-lien sewer system revenue bonds. The outlook is stable. "The ratings reflect, in our opinion, the combination of a very strong enterprise risk profile and a very strong financial risk profile," said S&P Global Ratings credit analyst Tim Tung. The enterprise risk profile