The Columbia Ultra Short Municipal Bond Fund class I3 (ticker: USMFX) is a mutual fund that primarily invests in short-term municipal bonds. These bonds are issued by state and local governments to fund public projects and services. The fund aims to provide investors with a low-risk investment option that offers potential tax-exempt income. The "class I3" designation indicates that this fund is only available to institutional investors, such as large corporations or pension funds. With a focus on short-term bonds, this fund may be suitable for investors seeking stability and liquidity in their portfolio.