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| 1. Name and Address of Reporting Person * |  | KOSKI CHRISTINE L |  | 2. Issuer Name and Ticker or Trading Symbol SUN HYDRAULICS CORP [SNHY]
 | 5. Relationship of Reporting Person(s) to Issuer (Check all applicable)
 
| __X__ Director | __X__ 10% Owner |  
| _____ Officer (give title below) | _____ Other (specify below) |  |  |  |  
|  | 3. Date of Earliest Transaction (Month/Day/Year) 10/26/2011
 |  
|  | 4. If Amendment, Date Original Filed(Month/Day/Year) 
 | 6. Individual or Joint/Group Filing(Check Applicable Line) ___ Form filed by One Reporting Person
 _X_ Form filed by More than One Reporting Person
 |  
|  | Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned |  | 
| 
| 1.Title of Security (Instr. 3)
 | 2. Transaction Date (Month/Day/Year) | 2A. Deemed Execution Date, if any (Month/Day/Year) | 3. Transaction Code (Instr. 8)
 | 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)
 | 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)
 | 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)
 | 7. Nature of Indirect Beneficial Ownership (Instr. 4)
 |  
| Code | V | Amount | (A) or (D) | Price |  
| Common Stock | 10/26/2011 |  | S(1) |  | 5,127 | D | $
                    28.3949
                    (2) | 4,067,531 | D
                    (3) |  |  
| Common Stock | 10/27/2011 |  | S(1) |  | 3,900 | D | $
                    29.9091
                    (4) | 4,063,631 | D
                    (3) |  |  
| Common Stock | 10/27/2011 |  | S(1) |  | 14,075 | D | $
                    30.6058
                    (5) | 4,049,556 | D
                    (3) |  |  
| Common Stock | 10/26/2011 |  | S(6) |  | 5,174 | D | $
                    28.3892
                    (7) | 362,256 | D
                    (8) |  |  
| Common Stock | 10/27/2011 |  | S(6) |  | 3,953 | D | $
                    29.913
                    (9) | 358,303 | D
                    (8) |  |  
| Common Stock | 10/27/2011 |  | S(6) |  | 9,068 | D | $
                    30.5701
                    (10) | 349,235 | D
                    (8) |  |  
| Common Stock |  |  |  |  |  |  |  | 443,953.427 | D
                    (11) |  |  
| Common Stock |  |  |  |  |  |  |  | 230,550 | D
                    (12) |  |  
| Common Stock |  |  |  |  |  |  |  | 63,611 | D
                    (13) |  |  
| Common Stock |  |  |  |  |  |  |  | 4,800 | I
                    (14) | BY KOSKI MANAGEMENT, INC. |  | 
| 1. Title of Derivative Security (Instr. 3)
 | 2. Conversion or Exercise Price of Derivative Security | 3. Transaction Date (Month/Day/Year) | 3A. Deemed Execution Date, if any (Month/Day/Year) | 4. Transaction Code (Instr. 8)
 | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)
 | 6. Date Exercisable and Expiration Date (Month/Day/Year)
 | 7. Title and Amount of Underlying Securities (Instr. 3 and 4)
 | 8. Price of Derivative Security (Instr. 5)
 | 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)
 | 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)
 | 11. Nature of Indirect Beneficial Ownership (Instr. 4)
 | 
| Code | V | (A) | (D) | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 
| * | If the form is filed by more than one reporting person, see Instruction 4(b)(v). | 
| ** | Intentional misstatements or omissions of facts constitute Federal Criminal Violations.  See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a). | 
| (1) | Sales were effected pursuant to a Rule 10b5-1 trading plan adopted by the Koski Family Limited Partnership on September 30, 2011. | 
| (2) | The range of prices for the transactions reported is $28.00 - $28.68.  The undersigned hereby undertakes to provide upon request by the Commission staff, the issuer, or a security holder of the issuer, full information regarding the number of shares purchased or sold at each separate price. | 
| (3) | Shares owned directly by Koski Family Limited Partnership.  Shares owned indirectly by Beverly Koski, Christine L. Koski, Robert C. Koski and Thomas L. Koski, each of whom is a general partner of the partnership or the controlling person of a corporate general partner of the partnership. | 
| (4) | The range of prices for the transactions reported is $29.14 - $30.12.  The undersigned hereby undertakes to provide upon request by the Commission staff, the issuer, or a security holder of the issuer, full information regarding the number of shares purchased or sold at each separate price. | 
| (5) | The range of prices for the transactions reported is $30.14 - $31.00.  The undersigned hereby undertakes to provide upon request by the Commission staff, the issuer, or a security holder of the issuer, full information regarding the number of shares purchased or sold at each separate price. | 
| (6) | Sales were effected pursuant to a Rule 10b5-1 trading plan adopted by Christine Koski on September 30, 2011. | 
| (7) | The range of prices for the transactions reported is $28.00 - $28.67.  The undersigned hereby undertakes to provide upon request by the Commission staff, the issuer, or a security holder of the issuer, full information regarding the number of shares purchased or sold at each separate price. | 
| (8) | Shares owned directly by Christine L. Koski. | 
| (9) | The range of prices for the transactions reported is $29.13 - $30.10.  The undersigned hereby undertakes to provide upon request by the Commission staff, the issuer, or a security holder of the issuer, full information regarding the number of shares purchased or sold at each separate price. | 
| (10) | The range of prices for the transactions reported is $30.14 - $30.92.  The undersigned hereby undertakes to provide upon request by the Commission staff, the issuer, or a security holder of the issuer, full information regarding the number of shares purchased or sold at each separate price. | 
| (11) | Shares owned directly by Beverly Koski. | 
| (12) | Shares owned directly by Thomas L. Koski. | 
| (13) | Shares owned directly by Robert C. Koski. | 
| (14) | Shares owned indirectly by Beverly Koski. |