October 16, 2007

Supplement

SUPPLEMENT DATED OCTOBER 16, 2007 TO THE STATEMENT OF ADDITIONAL INFORMATION OF
MORGAN STANLEY HIGH YIELD SECURITIES INC.
Dated December 29, 2006

The following disclosure is hereby added in the section of the Fund’s Statement of Additional Information entitled ‘‘II. Description of the Fund and Its Investments and Risks — B. Investment Strategies and Risks’’:

Public Bank Loans. The Fund may invest in public loans made by banks or other financial institutions, which may be rated investment grade (Baa or higher by Moody’s Investors Service (‘‘Moody’s’’) BBB or higher by Standard & Poor’s Rating Group, a division of The McGraw-Hill Companies, Inc. (‘‘S&P’’)) or below investment grade (below Baa by Moody’s or below BBB by S&P). Public bank loans are privately negotiated loans for which information about the issuer has been made publicly available. However, public bank loans are not registered under the Securities Act of 1933 and are not publicly traded. They usually are second lien loans normally lower in priority of payment to senior loans, but have seniority in a company’s capital structure to other claims, such as subordinated corporate bonds or publicly-issued equity so that in the event of bankruptcy or liquidation, the company is required to pay down these second lien loans prior to such other lower-ranked claims on their assets. Bank loans normally pay floating rates that reset frequently, and as a result, protect investors from increases in interest rates.

Bank loans generally are negotiated between a borrower and several financial institutional lenders represented by one or more lenders acting as agent of all the lenders. The agent is responsible for negotiating the loan agreement that establishes the terms and conditions of the loan and the rights of the borrower and the lenders, monitoring any collateral, and collecting principal and interest on the loan. By investing in a loan, the Fund becomes a member of a syndicate of lenders. Certain bank loans are illiquid, meaning the Fund may not be able to sell them quickly at a fair price. Illiquid securities are also difficult to value. To the extent a bank loan has been deemed illiquid, it will be subject to a Fund’s restrictions on investment in illiquid securities. The secondary market for bank loans may be subject to irregular trading activity, wide bid/ask spreads and extended trade settlement periods.

Bank loans are subject to the risk of default. Default in the payment of interest or principal on a loan will result in a reduction of income to a Fund, a reduction in the value of the loan, and a potential decrease in the Fund’s net asset value. The risk of default will increase in the event of an economic downturn or a substantial increase in interest rates. Bank loans are subject to the risk that the cash flow of the borrower and property securing the loan or debt, if any, may be insufficient to meet scheduled payments. As discussed above, however, because bank loans reside higher in the capital structure than high yield bonds, default losses have been historically lower in the bank loan market. Bank loans that are rated below investment grade share the same risks of other below investment grade securities.

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Non-fundamental policy number four in the section of the Fund’s Statement of Additional Information entitled ‘‘II. Description of the Fund and Its Investments and Risks — C. Fund Policies/Investment Restrictions’’ is hereby deleted.

PLEASE RETAIN THIS SUPPLEMENT FOR FUTURE REFERENCE.