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 * Sheridan Scott Daniel   2. Issuer Name and Ticker or Trading Symbol THINKORSWIM GROUP INC. [SWIM] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 600 WEST CHICAGO AVENUE, SUITE 100 3. Date of Earliest Transaction (Month/Day/Year) 02/15/2009 (Street) CHICAGO, IL 60610 4. If Amendment, Date Original Filed(Month/Day/Year) 02/18/2009 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 02/15/2009   J   58,461 (1) (3) A $ 0 (1) 4,499,364 (3) D   Common Stock 02/15/2009   J   332 (2) (4) A $ 0 (2) 25,189 (4) I By Scott Sheridan Trust

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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
Sheridan Scott Daniel 600 WEST CHICAGO AVENUE SUITE 100 CHICAGO, IL 60610	X

Signatures

/s/ Scott Daniel Sheridan		02/20/2009
**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)	On 2/15/09, filer became entitled to receive 58,461 shares of the Issuer's common stock pursuant to the Agreement and Plan of Merger ("Agreement") among Investools Inc., thinkorswim Group, Inc. and Atomic Acquisition Corp. dated 9/18/06, under which the companies merged on 2/15/07. Under the Agreement certain former shareholders, including filer, were to receive additional shares of Issuer's stock, for no additional consideration, if the price of Issuer's stock was below a certain threshold as of 2/15/09. Since the trading price was below the threshold, the filer acquired additional shares as of 2/15/09, pursuant to a formula in the Agreement, which provides that for purposes of determining the shares issuable, the stock would be valued at a weighted average of the 20 trading days prior to 2/15/09, $8.00. The filer's right to receive additional shares became fixed and irrevocable on 2/15/07, the effective date of the merger.
(2)	On 2/15/09 the Scott Sheridan Trust became entitled to receive additional 332 shares for no additional consideration under the Agreement pursuant to the right described in footnote 1.
(3)	The number of securities listed as acquired and beneficially owned following the transaction was inadvertently previously reported as 50,145 and 4,491,048, respectively, on a Form 4 filed on February 18, 2009.
(4)	The number of securities listed as acquired and beneficially owned following the transaction was inadvertently previously reported as 285 and 25,142, respectively, on a Form 4 filed on February 18, 2009.

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