Interval Funds have several key similarities with open-end mutual funds, but they are not identical.   Mutual funds and interval funds both offer shares on a continuous basis at NAV.  Mutual funds and interval funds are both “40 Act Funds” that provide investor protections from the Investment Company Act of 1940.   Mutual funds by definition allow daily redemptions, but interval Funds provide limited liquidity at set intervals.  This diagram, from recently launched Sierra Total Return Fund, (sponsored by Medley Management) compares and contrasts Open-End Mutual Funds, Closed-End Funds, and Interval Funds:

For additional Information, see: What is an interval fund?.