UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 Information to be included in statements filed pursuant to Rule 13d-1 (b) (c) and (d) and Amendments thereto filed pursuant to Rule 13d-2 (b). Sinclair Broadcast Group, Inc. (Name of Issuer) Senior Unsecured Convertible Bonds (Title of Class of Securities) 829226AW9 (CUSIP Number) April 6, 2009 (Date of Event which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is filed: [x] Rule 13d-1 (b) [ ] Rule 13d-1 (c) [ ] Rule 13d-1 (d) *The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page. The information required in the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes). SCHEDULE 13G Issuer: Sinclair Broadcast Group, Inc. CUSIP No.: 829226AW9 1 NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS MacKay Shields LLC IRS# 13-4080466; 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) (b) 3 SEC USE ONLY 4 CITIZENSHIP OR PLACE OF ORGANIZATION Delaware (United States) NUMBER OF SHARES 5 SOLE VOTING POWER 2,590,840 BENEFICIALLY 6 SHARED VOTING POWER 0 OWNED BY EACH 7 SOLE DISPOSITIVE POWER 2,590,840 REPORTING PERSON 8 SHARED DISPOSITIVE POWER 0 WITH 9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON Total: 2,590,840 10 CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES Not Applicable 11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 11 5.29% 12 TYPE OF REPORTING PERSON IA SCHEDULE 13G Issuer: Sinclair Broadcast Group, Inc. CUSIP No.: 829226AW9 ITEM 1 (a) Name of Issuer: Sinclair Broadcast Group, Inc. (b) Address of Issuer's Principal Executive Offices: 10706 Beaver Dam Road Hunt Valley, MD 21030 ITEM 2(a) Name of Person Filing: MacKay Shields LLC (b) Address of Principal Business Office: 9 West 57th Street New York, NY 10019 (c) Citizenship: United States (d) Title of Class of Securities: Senior Unsecured Convertible Bonds (e) CUSIP Number: 829226AW9 ITEM 3 If this statement is filed pursuant to Sections 240. 13d-1(b), or 240.13d-2(b) or (c), check whether the person filing is a: (a) [ ] Broker or dealer registered under Section 15 of the Act (15 U.S.C. 78o); (b) [ ] Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c); (c) [ ] Insurance Company as defined in section 3(a)(19) of the Act (15 U.S.C. 78C); (d) [ ] Investment company registered under Section 8 of the Investment Company Act if 1940 (15 U.S.C. 80a-8); (e) [X] An investment adviser in accordance with Section 240.13d-1(b)(1)(ii)(E); (f) [ ] An employee benefit plan or endowment fund in accordance with Section 240.13d-1(b)(1)(ii)(F); (g) [ ] A parent holding company or control person in accordance with Section 240.13d-1(b)(1)(ii)(G); (h) [ ] A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813); (i) [ ] A church plan that is excluded from the definition of an insurance company under Section 3 (c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3); (j) [ ] Group, in accordance with section 240.13d-1 (b)(1)(ii)(J). SCHEDULE 13G Issuer: Sinclair Broadcast Group, Inc. CUSIP No.: 829226AW9 ITEM 4. Ownership. MacKay Shields LLC, an investment adviser registered under Section 203 of the Investment Advisers Act of 1940, is deemed to be the beneficial owner of 2,590,840 shares or 5.29% of the common stock issuable upon the conversion of 50,910 of the 3% convertible bonds due May 15, 2027 of the Issuer with a conversion rate of 50.8906. The percent of class is calculated based on 48,967,839 shares of common stock outstanding, which is calculated by adding 46,376,999 (the number of shares of common stock outstanding of the company as of March 31, 2009) and 2,590,840 (the number of shares of common stock deemed held as a result of the beneficial ownership of the convertible bond). ITEM 5. Ownership of Five Percent or Less of a Class. Not Applicable ITEM 6. OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON Not Applicable ITEM 7. IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY OR CONTROL PERSON. Not Applicable ITEM 8. Identification and Classification of Members of the Group. Not Applicable ITEM 9. Notice of Dissolution of Group Not Applicable ITEM 10. Certification By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of such securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose of effect. SIGNATURE After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct. Date: April 6, 2009 Signature: /s/ Rene A. Bustamante Name/Title: Rene A. Bustamante Chief Compliance Officer