The rating on Ector County, Texas' certificates of obligation and tax notes is based on the limited-tax pledge of the county and reflects its: Economic base, which is concentrated in the oil and gas sector; Consistently strong financial performance and position; and Low overall debt burden coupled with a rapid amortization schedule. Located in west Texas in the Permian Basin region, Ector County is a major oil field supply and service center, as well as a retail and medical center for the surrounding region. The tax base is moderately concentrated with the 10 leading taxpayers--six are in the oil and gas industry, representing 27% of taxable assessed value (AV). Oil and gas properties represent 21% of the tax base. In