Ownership Submission
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 *
SHEEHAN KEVIN J
   2. Issuer Name and Ticker or Trading Symbol
INVESTORS FINANCIAL SERVICES CORP [IFIN] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
Chief Executive Officer
(Last)
(First)
(Middle)
INVESTORS BANK & TRUST COMPANY, 200 CLARENDON STREET		 3. Date of Earliest Transaction (Month/Day/Year)
04/18/2006
(Street)

BOSTON, MA 02116		 4. If Amendment, Date Original Filed(Month/Day/Year)
 6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ 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 04/18/2006   A   4,222 A $ 22.219 921,034 D  
Common Stock 04/18/2006   A   1,902 A $ 33.125 922,936 D  
Common Stock 04/18/2006   A   1,516 A $ 10.7579 924,452 D  
Common Stock 04/18/2006   A   56,600 A $ 7.5 981,052 D  
Common Stock 04/18/2006   A   18,208 A $ 10.7579 999,260 D  
Common Stock 04/18/2006   S   4,222 D $ 48.12 995,038 D  
Common Stock 04/18/2006   S   1,902 D $ 48.13 993,136 D  
Common Stock 04/18/2006   S   1,516 D $ 48.28 991,620 D  
Common Stock 04/18/2006   S   56,600 D $ 48.1466 935,020 D  
Common Stock 04/18/2006   S   18,208 D $ 48.0276 916,812 D  
Common Stock 04/19/2006   S   74,000 D $ 48.6635 842,812 D  
Common Stock 04/19/2006   S   27,000 D $ 48.5 815,812 D  

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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
Common Stock (right to buy) $ 22.219 04/18/2006   M     4,222 08/15/2000(1) 11/12/2006 Common Stock 4,222 $ 0 1,212,620 D  
Common Stock (right to buy) $ 33.125 04/18/2006   M     1,902 01/16/2001(1) 11/12/2006 Common Stock 1,902 $ 0 1,210,718 D  
Common Stock (right to buy) $ 10.7579 04/18/2006   M     1,516 01/14/2000(1) 11/12/2006 Common Stock 1,516 $ 0 1,209,202 D  
Common Stock (right to buy) $ 7.5 04/18/2006   M     56,600 02/23/1999(1) 11/12/2006 Common Stock 56,600 $ 0 1,152,602 D  
Common Stock (right to buy) $ 10.7579 04/18/2006   M     18,208 01/14/2000(1) 11/12/2006 Common Stock 18,208 $ 0 1,134,394 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
SHEEHAN KEVIN J
INVESTORS BANK & TRUST COMPANY
200 CLARENDON STREET
BOSTON, MA 02116		       Chief Executive Officer  

Signatures

 Kevin J. Sheehan   04/20/2006
**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) Options granted pursuant to the Company's 1995 Stock Plan and became exercisable on the date of the grant.

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