...Standard & Poor's Ratings Services assigned its '##-' long-term rating and stable outlook to Celina, Texas' series 2015 combination tax and revenue certificates of obligation and affirmed its '##-' underlying rating (SPUR), with a stable outlook, on the city's existing debt. An ad valorem tax levy and limited surplus revenue from the city's waterworks and sewer system secure the certificates. Management plans to use series 2015 certificate proceeds to fund various capital improvement projects. The city pledges its ad valorem tax levy as payment for the certificates within the limits prescribed by law. The Texas Constitution limits the city's maximum ad valorem tax rate to $2.50 per $100 of taxable assessed valuation (AV). In our view, significant flexibility remains between the current tax rate of 65 cents per $100 of AV and the maximum amount allowed by state law. The rating reflects our opinion of the following factors for the city, specifically its:...