Investment manager Legg Mason (NYSE: LM) has filed paperwork with regulators to launch its first exchange traded fund.

According to the regulatory paperwork, the Legg Mason Western Asset Ultra-Short Duration ETF will be an actively managed bond fund that invests in U.S. dollar-denominated short-term, inveterate grade fixed-income securities, including money market securities and short-term debt securities, corporate debt securities, bank obligations, commercial paper, asset-backed and mortgage-backed securities, structured securities and instruments and securities issued by the U.S. and foreign governments.

The new fund’s duration date will be one year or less. IndexUniverse points out that the proposed Legg Mason fund almost exactly mimics the PIMCO Enhanced Short Maturity Strategy ETF (NYSEArca: MINT), which holds short-term investment-grade debt with a duration of 0.99 years. MINT has an expense ratio of 0.35%. [ETF Chart of the Day: MINT]