First Trust Exchange-Traded Fund III - First Trust Ultra Short Duration Municipal ETF is an exchange traded fund launched and managed by First Trust Advisors L.P. The fund invests in fixed income markets of the United States. It invests in investment grade, tax exempt municipal debt securities issued by or on behalf of states, territories or possessions of the U.S. and the District of Columbia and their political subdivisions, agencies, authorities and other instrumentalities rated Baa3 by Moody's or BBB- by S&P or Fitch. The fund is expected to maintain the weighted average duration of less than one year. It seeks to benchmark the performance of its portfolio against the Bloomberg Municipal Short-Term Index and the Bloomberg Municipal Bond Index. First Trust Exchange-Traded Fund III - First Trust Ultra Short Duration Municipal ETF was formed on November 1, 2018 and is domiciled in the United States.