SONE S1 Corp. (MM)

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CUSIP No. 78463B101

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1. NAME OF REPORTING PERSON
 Water Island Capital, LLC
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2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
 Not Applicable
 (a) [ ]
 (b) [ ]
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3. SEC USE ONLY

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4. CITIZENSHIP OR PLACE OF ORGANIZATION
 Delaware
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NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:
 5. SOLE VOTING POWER
 5765326
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 6. SHARED VOTING POWER
 None
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 7. SOLE DISPOSITIVE POWER
 5765326
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 8. SHARED DISPOSITIVE POWER
 None
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9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
 5765326
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10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES
 Not Applicable
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11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
 10.446
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12. TYPE OF REPORTING PERSON
 IA
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CUSIP No. 78463B101
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Item 1(a) Name of Issuer:
AMERICAN DENTAL PARTNERS INC
Item 1(b) Address of Issuer's Principal Executive Offices:
401 EDGEWATER PLACE
SUITE 430
WAKEFILED, MA 01880

Item 2(a) Name of Person(s) Filing:

WATER ISLAND CAPITAL LLC ("WIC")
Item 2(b) Address of Principal Business Office:

41 MADISON AVE 42nd FLOOR
NEW YORK NY 10010

Item 2(c) Citizenship:
WIC is a Delaware limited liability company.

Item 2(d) Title of Class of Securities:
Common Stock

Item 2(e) CUSIP Number:
78463B101

Item 3 Type of Person:
(e) WIC is an Investment Adviser in accordance with Rule 13d-1(b)(1)(ii)(F).

Item 4 Ownership:
(a) Amount beneficially owned:
 5765326
(b) Percent of class:
 10.446
(c) Number of shares as to which such person has:
(i) Sole power to vote or to direct the vote:
 5765326
(ii) Shared power to vote or to direct the vote:
 None
(iii) Sole power to dispose or direct the disposition of:
 5765326
(iv) Shared power to dispose or direct the disposition of:
 None

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:

 WIC is an Investment Adviser registered under section 203 of the
 Investment Advisers Act of 1940, as amended.

CUSIP No. 78463B101
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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 are 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
the securities and were not acquired and are not held in connection with or
as a participant in any transaction having that purpose or 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: 2/09/2012

WATER ISLAND CAPITAL LLC

By: /s/ Matthew Hemberger
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Matthew Hemberger
Chief Financial Officer