Supplement to Prospectus Dated March 1, 1997 of Harris Associates Investment
                                     Trust
 
                        The Oakmark International Funds
 
    David G. Herro and Michael J. Welsh are the portfolio manager and the
co-manager, respectively, of each of The Oakmark International Fund and The
Oakmark International Small Cap Fund.
 
                           The Oakmark Small Cap Fund
 
                              Closing of the Fund
 
    Effective June 20, 1997, The Oakmark Small Cap Fund was closed to purchases
by new investors except as described below. The Fund took this step to
facilitate management of the Fund's portfolio.
 
    You may purchase shares of the Fund if:
 
    - You are already a shareholder of the Fund in your own name or beneficially
      through an intermediary;
 
    - You purchase through an employee benefit plan whose records are maintained
      by a trust company or plan administrator and whose investment alternatives
      include shares of the Fund; or
 
    - You purchase for an annuity account offered by a company that includes
      shares of the Fund as an investment alternative for such account.
 
    In addition, you may exchange shares of another fund of the Trust or Oakmark
Units for shares of the Fund as described in the prospectus under "How to
Purchase Shares--By Exchange."
 
    The Trust reserves the right to re-open the Fund to new investors or to
modify the extent to which the sale of shares is limited.
 
                           The Oakmark Balanced Fund
 
                                 Change of Name
 
    As of the close of business on July 14, 1997, the name of The Oakmark
Balanced Fund will be changed to The Oakmark Equity and Income Fund.
 
                    This Supplement is Dated July 14, 1997.