FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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(Print or Type Responses)

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) (Last) (First) (Middle) 3. Date of Earliest Transaction (Month/Day/Year) 07/19/2011 (Street)   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 (City) (State) (Zip) 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 07/19/2011   S(1)   3,149 D $ 33.5409 (2) 4,081,150 (3) D (4)   Common Stock 07/20/2011   S(1)   200 D $ 33.515 (5) 4,080,950 D (4)   Common Stock 07/19/2011   S(6)   2,925 D $ 33.5401 (7) 78,411 (8) D (9)   Common Stock 07/20/2011   S(6)   200 D $ 33.515 (10) 78,211 D (9)   Common Stock               375,285 (11) D (12)   Common Stock               443,953.427 (13) D (14)   Common Stock               230,550 (15) D (16)   Common Stock               4,800 (17) I (18) BY KOSKI MANAGEMENT, INC.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

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

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
KOSKI CHRISTINE L	X	X
KOSKI BEVERLY		X
KOSKI FAMILY LP		X
KOSKI ROBERT C		X
KOSKI THOMAS L		X

Signatures

Gregory C. Yadley, as Attorney-in-Fact for CHRISTINE L. KOSKI, BEVERLY KOSKI, KOSKI FAMILY LIMITED PARTNERSHIP, ROBERT C. KOSKI AND THOMAS L. KOSKI		07/21/2011
**Signature of Reporting Person		Date

Explanation of Responses:

*	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 June 27, 2011.
(2)	The range of prices for the transactions reported is $33.50 - $33.57. 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)	Includes 1,361,433 shares issued as a result of three-for-two stock dividend declared in June 2011 to shareholders of record on June 30, 2011.
(4)	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.
(5)	The range of prices for the transactions reported is $33.50 - $33.53. 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 Robert C. Koski on June 27, 2011.
(7)	The range of prices for the transactions reported is $33.50 - $33.58. 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)	Includes 27,112 shares issued as a result of three-for-two stock dividend declared in June 2011 to shareholders of record on June 30, 2011.
(9)	Shares owned directly by Robert C. Koski.
(10)	The range of prices for the transactions reported is $33.50 - $33.53. 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)	Includes 125,095 shares issued as a result of three-for-two stock dividend declared in June 2011 to shareholders of record on June 30, 2011.
(12)	Shares owned directly by Christine L. Koski.
(13)	Includes 147,984 shares issued as a result of three-for-two stock dividend declared in June 2011 to shareholders of record on June 30, 2011.
(14)	Shares owned directly by Beverly Koski.
(15)	Includes 76,850 shares issued as a result of three-for-two stock dividend declared in June 2011 to shareholders of record on June 30, 2011.
(16)	Shares owned directly by Thomas L. Koski.
(17)	Includes 1,600 shares issued as a result of three-for-two stock dividend declared in June 2011 to shareholders of record on June 30, 2011.
(18)	Shares owned indirectly by Beverly Koski.

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