BlackRock MuniYield Quality Fund III, Inc. (the Fund), formerly BlackRock MuniYield Insured Fund, Inc., is a non-diversified, closed-end management investment company. The Fund's investment objective is to provide current income exempt from Federal income taxes. The Fund seeks to achieve its investment objective by investing at least 80% of its assets in municipal obligations exempt from federal income taxes. The Fund invests primarily in long-term municipal obligations that are investment grade quality at the time of investment and at least 80% of its assets in municipal obligations that are covered by insurance guaranteeing the timely payment of principal at maturity and interest when due. The Fund invests in sectors, such as transportation, county/city/special district/school district, utilities, state, education, health, housing and corporate. The Fund's investment advisor is BlackRock Advisors, LLC.