Exhibit 2

VOTING AGREEMENT

THIS VOTING AGREEMENT (this “Agreement”) is made and entered into as of January 8, 2009 by and between TD AMERITRADE Holding Corporation, a Delaware corporation (“Parent”), and the undersigned Stockholder (the “Stockholder”) of thinkorswim Group Inc., a Delaware corporation (the “Company”).

WITNESSETH:

WHEREAS, Parent, Tango Acquisition Corporation One, a Delaware corporation and wholly-owned subsidiary of Parent (“Merger Sub One”), Tango Acquisition Corporation Two, a Delaware corporation and wholly-owned subsidiary of Parent (“Merger Sub Two”), and the Company have entered into an Agreement and Plan of Merger of even date herewith (the “Merger Agreement”), which provides for, among other things, and as a single integrated transaction, the merger of Merger Sub One with and into the Company (the “First Step Merger”) pursuant to which all outstanding shares of capital stock of the Company will be converted into the right to receive the consideration set forth in the Merger Agreement. As soon as practicable following the First Step Merger, Parent will cause the Company to merge with and into Merger Sub Two (the “Second Step Merger” and, taken together with the First Step Merger, the “Merger”).

WHEREAS, the Stockholder is the beneficial owner (as defined in Rule 13d-3 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”)) of that number of shares of the outstanding capital stock of the Company, and the holder of options to purchase such number of shares of capital stock of the Company, in each case, as set forth on the signature page of this Agreement.

WHEREAS, as a condition and inducement to the willingness of Parent, Merger Sub One and Merger Sub Two to enter into the Merger Agreement, the Stockholder (in the Stockholder’s capacity as such) has agreed to enter into this Agreement.

NOW, THEREFORE, intending to be legally bound, the parties hereto agree as follows:

1. Certain Definitions. All capitalized terms that are used but not defined herein shall have the respective meanings ascribed to them in the Merger Agreement. For all purposes of and under this Agreement, the following terms shall have the following respective meanings:

(a) “Expiration Date” shall mean the earlier to occur of (i) such date and time as the Merger Agreement shall have been validly terminated pursuant to Article VIII thereof, or (ii) such date and time as the Merger shall become effective in accordance with the terms and provisions of the Merger Agreement.

(b) “Person” shall mean any individual, corporation, limited liability company, general or limited partnership, trust, unincorporated association or other entity of any kind or nature, or any governmental authority.

(c) “Shares” shall mean (i) all equity securities of the Company (including all shares of Company Common Stock, Company Preferred Stock and all Company Options and other

rights to acquire shares of Company Common Stock) owned by the Stockholder as of the date hereof, and (ii) all additional equity securities of the Company (including all additional shares of Company Common Stock, Company Preferred Stock and all additional Company Options, warrants and other rights to acquire shares of Company Common Stock) of which the Stockholder acquires ownership during the period from the date of this Agreement through the Expiration Date (including by way of stock dividend or distribution, split-up, recapitalization, combination, exchange of shares and the like).

(d) “Transfer” A Person shall be deemed to have effected a “Transfer” of a Share if such Person directly or indirectly (i) sells, pledges, encumbers, assigns, grants an option with respect to (or otherwise enters into a hedging arrangement with respect to), transfers, tenders or disposes of such Share or any interest in such Share, or (ii) enters into an agreement or commitment providing for the sale of, pledge of, encumbrance of, assignment of, grant of an option with respect to (or entry into a hedging arrangement with respect to), transfer, tender of or disposition of such Share or any interest therein, provided, for the avoidance of doubt “Transfer” does not include granting a proxy or voting or consent instructions with respect to any matter other than those specified in Section 3(a)(i), (ii) or (iii).

2. Transfer of Shares.

(a) Transfer Restrictions. The Stockholder shall not Transfer (or cause or permit the Transfer of) any of the Shares, or enter into any agreement relating thereto, except (i) by selling already-owned Shares either to pay the exercise price upon the exercise of a Company Option or to satisfy the Stockholder’s tax withholding obligation upon the exercise of a Company Option, in each case as permitted by any Company Option Plan, (ii) transferring Shares to Affiliates, immediate family members, a trust established for the benefit of Stockholder and/or for the benefit of one or more members of Stockholder’s immediate family or charitable organizations or upon the death of the Stockholder, provided that, as a condition to such Transfer, the recipient agrees to be bound by this Agreement and delivers a Proxy (as defined below) in the form attached hereto as Exhibit A, or (iii) with Parent’s prior written consent and in Parent’s sole discretion. Any Transfer, or purported Transfer, of Shares in breach or violation of this Agreement shall be void and of no force or effect.

(b) Transfer of Voting Rights. The Stockholder shall not deposit (or cause or permit the deposit of) any Shares in a voting trust or grant any proxy or enter into any voting agreement or similar agreement in contravention of the obligations of the Stockholder under this Agreement with respect to any of the Shares.

3. Agreement to Vote Shares.

(a) At every meeting of the Stockholders of the Company, and at every adjournment or postponement thereof, and on every action or approval by written consent of the Stockholders of Company, the Stockholder (in the Stockholder’s capacity as such), to the extent not voted by the Person(s) appointed under the Proxy, shall, or shall cause the holder of record on any applicable record date to, vote all Shares that are then-owned by such Stockholder and entitled to vote or act by written consent:

(i) in favor of the adoption of the Merger Agreement, and in favor of each of the other actions contemplated by the Merger Agreement and any action required in furtherance thereof;

(ii) against approval of any proposal made in opposition to, in competition with, or would result in a breach of, the Merger Agreement or the Merger or any other transactions contemplated by the Merger Agreement; and

(iii) against any of the following actions (other than those actions that relate to the Merger and any other transactions contemplated by the Merger Agreement): (A) any merger, consolidation, business combination, sale of assets, reorganization or recapitalization of or involving the Company or any of its Subsidiaries, (B) any sale, lease or transfer of all or substantially all of the assets of the Company or any of its Subsidiaries, (C) any reorganization, recapitalization, dissolution, liquidation or winding up of the Company or any of its Subsidiaries, (D) any material change in the capitalization of the Company or any of its Subsidiaries, or the corporate structure of the Company or any of its Subsidiaries, (E) any Acquisition Proposal or Acquisition Transaction or (F) any other action that is intended to, or would reasonably be expected to materially, impede, interfere with, delay, postpone, discourage or adversely affect the Merger or any other transactions contemplated by the Merger Agreement.

The Stockholder shall retain at all times the right to vote its Shares in its sole discretion and without any other limitation on those matters other than those set forth in clauses (i), (ii) and (iii) that are at any time or from time to time presented for consideration to the Company’s stockholders generally. For the avoidance of doubt, clauses (i), (ii) and (iii) shall not apply to votes, if any, solely on the election or removal of directors as recommended by the Company’s Board of Directors (provided such recommendation is not in violation of the terms of the Merger Agreement).

(b) In the event that a meeting of the Stockholders of the Company is held, the Stockholder shall, or shall cause the holder of record on any applicable record date to, appear at such meeting or otherwise cause the Shares to be counted as present thereat for purposes of establishing a quorum.

(c) The Stockholder shall not enter into any agreement or understanding with any Person to vote or give instructions in any manner inconsistent with the terms of this Section 3.

4. No Solicitation.

(a) The Stockholder shall immediately cease any and all existing activities, discussions or negotiations with any Persons conducted heretofore with respect to any Acquisition Proposal or Acquisition Transaction.

(b) At all times during the period commencing with the execution and delivery of this Agreement and continuing until the Expiration Date the Stockholder shall not, directly or indirectly:

(i) solicit, initiate or knowingly encourage, facilitate or induce any inquiry with respect to, or the making, submission or announcement of, an Acquisition Proposal or an Acquisition Transaction;

(ii) furnish to any Person (other than Parent, Merger Sub One, Merger Sub Two or any designees of Parent or the Merger Subs) any non-public information relating to the Company or any of its Subsidiaries, or afford access to the business, properties, assets, books or records of the Company or any of its Subsidiaries to any Person (other than Parent, Merger Sub One, Merger Sub Two or any designees of Parent or the Merger Subs), or take any other action, in each case in a manner that is intended or would be reasonably expected to assist or facilitate any inquiries or the making of any proposal that constitutes or could lead to an Acquisition Proposal or an Acquisition Transaction;

(iii) participate or engage in discussions or negotiations with any Person with respect to an Acquisition Proposal or an Acquisition Transaction; or

(iv) propose or agree to do any of the foregoing.

5. Agreement Not to Exercise Appraisal Rights. The Stockholder shall not exercise, and hereby irrevocably and unconditionally waives, any statutory rights (including, without limitation, under Section 262 of the DGCL) to demand appraisal of any Shares that may arise in connection with the Merger.

6. Directors and Officers. Notwithstanding any provision of this Agreement to the contrary, nothing in this Agreement shall limit or restrict a Stockholder who is a director or officer of the Company from acting in such capacity or fulfilling the obligations of such office, including by voting, in his capacity as a director of the Company, in the Stockholder’s sole discretion on any matter (it being understood that this Agreement shall apply to the Stockholder solely in the Stockholder’s capacity as a Stockholder of the Company). In this regard, the Stockholder shall not be deemed to make any agreement or understanding in this Agreement in Stockholder’s capacity as a director or officer of the Company. For the avoidance of doubt, nothing in Section 4 or elsewhere in this Agreement shall limit in any way the Company and its officers and directors from taking actions permitted by the Merger Agreement.

7. Irrevocable Proxy. Concurrently with the execution of this Agreement, the Stockholder shall deliver to Parent a proxy in the form attached hereto as Exhibit A (the “Proxy”), which shall be irrevocable to the fullest extent permissible by law, with respect to the Shares.

8. Update of Beneficial Ownership Information. Promptly following the written request of Parent, the Stockholder shall send to Parent a notice in the form of Exhibit B hereto, setting forth the number of Shares beneficially owned by such Stockholder as of the record date of the Company Stockholder Meeting.

9. Representations and Warranties of the Stockholder. The Stockholder hereby represents and warrants to Parent as follows:

(a) Power; Binding Agreement. The Stockholder has full power and authority to execute and deliver this Agreement and the Proxy, to perform the Stockholder’s obligations hereunder and to consummate the transactions contemplated hereby. This Agreement has been duly executed and delivered by the Stockholder, and, assuming this Agreement constitutes a valid and binding obligation of Parent, Merger Sub One and Merger Sub Two, constitutes a valid and binding obligation of the Stockholder, enforceable against the Stockholder in accordance with its terms, except that such enforceability may be limited by applicable bankruptcy, insolvency, reorganization, moratorium and other similar laws affecting or relating to creditors’ rights generally and is subject to general principles of equity (regardless of whether such enforceability is considered in a proceeding in equity or at law).

(b) No Conflicts. None of the execution and delivery by the Stockholder of this Agreement, the performance by the Stockholder of its obligations hereunder or the consummation by the Stockholder of the transactions contemplated hereby will (i) result in a violation or breach of any agreement to which the Stockholder is a party or by which the Stockholder may be bound, including any voting agreement or voting trust, except for violations, breaches or defaults that would not in any material respect impair or adversely effect the ability of Stockholder to perform its obligations under this Agreement, or (ii) violate any order, writ, injunction, decree, judgment, order, statute, rule, or regulation applicable to the Stockholder.

(c) Ownership of Shares. The Stockholder (i) is the sole beneficial owner of the shares of Company Common Stock set forth on the signature page of this Agreement, all of which are free and clear of any liens, adverse claims, charges, security interests, pledges or options, proxies, voting trusts or agreements, understandings or agreements, or any other rights or encumbrances whatsoever (“Encumbrances”) (except any Encumbrances arising under securities laws or arising hereunder or arising under Section 2.1 of the Stockholders’ Agreement, dated as of February 15, 2007, by and among the Company, the Stockholder and the other stockholders named therein), (ii) is the sole holder of the Company Options that are exercisable for the number of shares of Company Common Stock set forth on the signature page of this Agreement, all of which Company Options and shares of Company Common Stock issuable upon the exercise of such Company Options are, or in the case of Company Common Stock received upon exercise of an option after the date hereof will be, free and clear of any Encumbrances (except any Encumbrances arising under securities laws, arising under the plans pursuant to which such Company Options were granted or arising hereunder, or arising under Section 2.1 of the Stockholders’ Agreement, dated as of February 15, 2007, by and among the Company, the Stockholder and the other stockholders named therein), and (iii) except as set forth on the signature page to this Agreement, does not own, beneficially or otherwise, any securities of the Company other than the shares of Company Common Stock or options to purchase shares of Company Common Stock, and shares of Company Common Stock issuable upon the exercise of such Company Options, set forth on the signature page of this Agreement.

(d) Voting Power. The Stockholder has or will have sole voting power, sole power of disposition, sole power to issue instructions with respect to the matters specified in Section 2 and Section 3(a)(i), (ii) and (iii), and sole power to agree to all of the matters specified in Section 2 and Section 3(a)(i), (ii) or (iii), in each case with respect to all of the Shares, with no limitations,

qualifications or restrictions on such rights, subject to applicable federal securities laws and the terms of this Agreement and the terms of Section 2.1 of the Stockholders’ Agreement, dated as of February 15, 2007, by and among the Company, the Stockholder and the other stockholders named therein.

(e) No Finder’s Fees. No broker, investment banker, financial advisor, finder, agent or other Person is entitled to any broker’s, finder’s, financial adviser’s or other similar fee or commission in connection with this Agreement based upon arrangements made by or on behalf of the Stockholder in his or her capacity as such.

(f) Reliance by Parent. The Stockholder understands and acknowledges that Parent is entering into the Merger Agreement in reliance upon the Stockholder’s execution and delivery of this Agreement.

(g) No Legal Actions. Stockholder agrees that Stockholder will not in Stockholder’s capacity as a Stockholder of the Company bring, commence, institute, maintain, prosecute or voluntarily aid any action, claim, suit or cause of action, in law or in equity, in any court or before any governmental entity, which (i) challenges the validity of or seeks to enjoin the operation of any provision of this Agreement or (ii) alleges that the execution and delivery of this Agreement by Stockholder, either alone or together with the other Company voting agreements and proxies to be delivered in connection with the execution of the Merger Agreement, or the approval of the Merger Agreement by the Company Board, breaches any fiduciary duty of the Company Board or any member thereof.

10. Certain Restrictions. The Stockholder shall not, directly or indirectly, take any voluntary action that would make any representation or warranty of the Stockholder contained herein untrue or incorrect in any material respect.

11. Disclosure. The Stockholder shall permit Parent to publish and disclose in all documents and schedules filed with the SEC, and any press release or other disclosure document that Parent reasonably determines to be necessary or desirable in connection with the Merger and any transactions related to the Merger, the Stockholder’s identity and ownership of Shares and the nature of the Stockholder’s commitments, arrangements and understandings under this Agreement.

12. No Ownership Interest. Nothing contained in this Agreement shall be deemed to vest in Parent any direct or indirect ownership or incidence of ownership of or with respect to any Shares. Except as provided in this Agreement, all rights, ownership and economic benefits relating to the Shares shall remain vested in and belong to Stockholder.

13. Further Assurances. Subject to the terms and conditions of this Agreement, upon request of Parent, the Stockholder shall use commercially reasonable efforts to take, or cause to be taken, all actions, and to do, or cause to be done, all things necessary to fulfill such Stockholder’s obligations under this Agreement.

14. Stop Transfer Instructions. At all times commencing with the execution and delivery of this Agreement and continuing until the Expiration Date, in furtherance of this Agreement, the

Stockholder hereby authorizes the Company or its counsel to notify the Company’s transfer agent that there is a stop transfer order with respect to all of the Shares of the Stockholder (and that this Agreement places limits on the voting and transfer of such Shares).

15. Termination. This Agreement and the Proxy, and all rights and obligations of the parties hereunder and thereunder, shall terminate and shall have no further force or effect as of the Expiration Date. Notwithstanding the foregoing, nothing set forth in this Section 15 or elsewhere in this Agreement shall relieve either party hereto from liability, or otherwise limit the liability of either party hereto, for any intentional breach of this Agreement prior to such termination. Section 5 shall survive any termination of this Agreement.

16. Miscellaneous.

(a) Validity. The invalidity or unenforceability of any provision of this Agreement shall not affect the validity or enforceability of the other provisions of this Agreement, which will remain in full force and effect. In the event any Governmental Entity of competent jurisdiction holds any provision of this Agreement to be null, void or unenforceable, the parties hereto shall negotiate in good faith and execute and deliver an amendment to this Agreement in order, as nearly as possible, to effectuate, to the extent permitted by law, the original intent of the parties hereto with respect to such provision.

(b) Binding Effect and Assignment. This Agreement and all of the provisions hereof shall be binding upon and inure to the benefit of the parties hereto and their respective successors and permitted assigns, but neither this Agreement nor any of the rights, interests or obligations of the parties hereto may be assigned by either of the parties (whether by operation of law or otherwise) without prior written consent of the other.

(c) Amendments; Waiver. This Agreement may be amended by the parties hereto, and the terms and conditions hereof may be waived, only by an instrument in writing signed on behalf of each of the parties hereto, or, in the case of a waiver, by an instrument signed on behalf of the party waiving compliance.

(d) Specific Performance; Injunctive Relief. The parties hereto acknowledge that Parent shall be irreparably harmed and that there shall be no adequate remedy at law for a violation of any of the covenants or agreements of the Stockholder set forth herein. Therefore, it is agreed that, in addition to any other remedies that may be available to Parent upon any such violation, Parent shall have the right to enforce such covenants and agreements by specific performance, injunctive relief or by any other means available to Parent at law or in equity.

(e) Notices. All notices and other communications hereunder shall be in writing and shall be deemed given if delivered personally or by commercial delivery service, or sent via telecopy (receipt confirmed) to the parties at the following addresses or telecopy numbers (or at such other address or telecopy numbers for a party as shall be specified by like notice), or pursuant to such other instructions as may be designated in writing by the party to receive such notice:

If to Parent:

TD AMERITRADE Holding Corporation
4211 South 102^nd Street
Omaha, NE 68127
Attention: General Counsel
Telephone No.: (402) 331-7856
Telecopy No.: (443) 539-2009

with a copy to:

Wilson Sonsini Goodrich & Rosati
Professional Corporation
650 Page Mill Road
Palo Alto, California 94304-1050
Attention: Larry W. Sonsini, Martin W. Korman and Michael S. Ringler
Telephone No.: (650) 493-9300
Telecopy No.: (650) 493-6811

If to the Stockholder:

[                    ]
[                    ]
[                    ]

with a copy to:

Cleary Gottlieb Steen & Hamilton LLP
One Liberty Plaza
New York, New York 10006
Attention: Ethan A. Klingsberg and Benet J. O’Reilly
Telecopy No.: (212) 225-3999

(f) No Waiver. The failure of either party hereto to exercise any right, power or remedy provided under this Agreement or otherwise available in respect of this Agreement at law or in equity, or to insist upon compliance by any other party with its obligation under this Agreement, and any custom or practice of the parties at variance with the terms of this Agreement, shall not constitute a waiver by such party of such party’s right to exercise any such or other right, power or remedy or to demand such compliance.

(g) No Third Party Beneficiaries. This Agreement is not intended to confer and does not confer upon any person other than the parties hereto any rights or remedies hereunder.

(h) Governing Law. This Agreement shall be governed by and construed in accordance with the laws of the State of Delaware, regardless of the laws that might otherwise govern under applicable principles of conflicts of law thereof.

(i) Submission to Jurisdiction. Each of the parties hereto irrevocably consents to the exclusive jurisdiction and venue in the Court of Chancery of the State of Delaware or, if under applicable Law exclusive jurisdiction over such matter is vested in the federal courts, any court of the United States located in the State of Delaware in connection with any matter based upon or arising out of this Agreement or the matters contemplated herein, and to the fullest extent permitted by law, waives and covenants not to assert or plead any objection which they might otherwise have to such jurisdiction and venue.

(j) Rules of Construction. The parties hereto hereby waive the application of any law, regulation, holding or rule of construction providing that ambiguities in an agreement or other document will be construed against the party drafting such agreement or document.

(k) Entire Agreement. This Agreement and the Proxy contain the entire understanding of the parties hereto in respect of the subject matter hereof, and supersede all prior negotiations, agreements and understandings, both written and oral, between the parties hereto with respect to the subject matter hereof.

(l) Interpretation.

(i) Whenever the words “include,” “includes” or “including” are used in this Agreement they shall be deemed to be followed by the words “without limitation.”

(ii) The article and section headings contained in this Agreement are solely for the purpose of reference, are not part of the agreement of the parties hereto and shall not in any way affect or be deemed to affect the meaning or interpretation of this Agreement.

(m) Expenses. All fees, costs and expenses incurred in connection with this Agreement and the transactions contemplated hereby shall be paid by the party incurring such fees, costs and expenses.

(n) Counterparts. This Agreement may be executed in several counterparts, each of which shall be an original, but all of which together shall constitute one and the same agreement.

(o) No Obligation to Exercise Options or Warrants. Notwithstanding any provision of this Agreement to the contrary, nothing in this Agreement shall obligate the Stockholder to exercise any Company Option, warrant or other right to acquire any shares of Company Common Stock.

[Remainder of Page Intentionally Left Blank]

IN WITNESS WHEREOF, the undersigned have executed and caused to be effective this Agreement as of the date first above written.


TD AMERITRADE HOLDING CORPORATION						STOCKHOLDER

By:

						[ ]
Name:

Title:


						Shares beneficially owned as of the date hereof:

						shares of Company Common Stock

						shares of Company Common Stock issuable upon exercise of outstanding options

**** VOTING AGREEMENT ****

EXHIBIT A

IRREVOCABLE PROXY

The undersigned Stockholder (the “Stockholder”) of thinkorswim Group Inc., a Delaware corporation (the “Company”), hereby irrevocably (to the fullest extent permitted by law) appoints TD AMERITRADE Holding Corporation, a Delaware corporation (“Parent”), acting through any of its Chief Executive Officer, Chief Financial Officer or General Counsel, as the sole and exclusive attorneys and proxies of the undersigned, with full power of substitution and resubstitution, to vote and exercise all voting and related rights (to the full extent that the undersigned is entitled to do so) with respect to all of the shares of capital stock of the Company that now are or hereafter may be beneficially owned by the undersigned, and any and all other shares or equity securities of the Company issued or issuable in respect thereof on or after the date hereof (collectively, the “Shares”) in accordance with the terms of this Irrevocable Proxy until the Expiration Date (as defined below); provided, however, that such proxy and voting and related rights are expressly limited to the matters discussed in clauses (i) through (iii) in the fourth paragraph of this Irrevocable Proxy. Upon the undersigned’s execution of this Irrevocable Proxy, any and all prior proxies given by the undersigned with respect to any Shares are hereby revoked and the undersigned agrees not to grant any subsequent proxies with respect to the Shares until after the Expiration Date, provided, further, that the undersigned may grant subsequent proxies with respect to any matter other than those specified in clauses (i) through (iii) in the fourth paragraph of this Irrevocable Proxy.

This Irrevocable Proxy is irrevocable to the fullest extent permitted by law, is coupled with an interest and is granted pursuant to that certain Voting Agreement of even date herewith by and between Parent and the undersigned Stockholder (the “Voting Agreement”), and is granted as a condition and inducement to the willingness of Parent, Tango Acquisition Corporation One, a Delaware corporation and wholly-owned subsidiary of Parent (“Merger Sub One”), Tango Acquisition Corporation Two, a Delaware corporation and wholly-owned subsidiary of Parent (“Merger Sub Two”), to enter into that certain Agreement and Plan of Merger of even date herewith (the “Merger Agreement”), among Parent, Merger Sub One, Merger Sub Two and the Company. The Merger Agreement provides for, among other things, and as a single integrated transaction, the merger of Merger Sub One with and into the Company (the “First Step Merger”) pursuant to which all outstanding shares of capital stock of the Company will be converted into the right to receive the consideration set forth in the Merger Agreement. As soon as practicable following the First Step Merger, Parent will cause the Company to merge with and into Merger Sub Two (the “Second Step Merger” and, taken together with the First Step Merger, the “Merger”).

As used herein, the term “Expiration Date” shall mean the earlier to occur of (i) such date and time as the Merger Agreement shall have been validly terminated pursuant to Article VIII thereof, or (ii) such date and time as the Merger shall become effective in accordance with the terms and provisions of the Merger Agreement.

The attorneys and proxies named above, and each of them, are hereby authorized and empowered by the undersigned, at any time prior to the Expiration Date, to act as the undersigned’s attorney and proxy to vote the Shares, and to exercise all voting, consent and similar rights of the undersigned with respect to the Shares (including, without limitation, the power to execute and

deliver written consents) at every annual, special, adjourned or postponed meeting of stockholders of the Company and in every written consent in lieu of such meeting:

(i) in favor of the adoption of the Merger Agreement, and in favor of each of the other actions contemplated by the Merger Agreement and any action required in furtherance thereof;

(ii) against approval of any proposal made in opposition to, or in competition with, the Merger Agreement or the Merger or any other transactions contemplated by the Merger Agreement; and

(iii) against any of the following actions (other than those actions that relate to the Merger and any other transactions contemplated by the Merger Agreement): (A) any merger, consolidation, business combination, sale of assets, reorganization or recapitalization of or involving the Company or any of its Subsidiaries, (B) any sale, lease or transfer of all or substantially all of assets of the Company or any of its Subsidiaries, (C) any reorganization, recapitalization, dissolution, liquidation or winding up of the Company or any of its Subsidiaries, (D) any material change in the capitalization of the Company or any of its Subsidiaries, or the corporate structure of the Company or any of its Subsidiaries, (E) any Acquisition Proposal or Acquisition Transaction or (F) any other action that is intended to, or would reasonably be expected to materially, impede, interfere with, delay, postpone, discourage or adversely affect the Merger or any other transactions contemplated by the Merger Agreement.

The attorneys and proxies named above may not exercise this Irrevocable Proxy on any other matter. The undersigned Stockholder may vote the Shares in its sole discretion on all other matters. For the avoidance of doubt, clauses (i) through (iii) in the fourth paragraph of this Irrevocable Proxy shall not apply to votes, if any, on the election or removal of directors as recommended by the Company’s Board of Directors (provided such recommendation is not in violation of the terms of the Merger Agreement).

Any obligation of the undersigned hereunder shall be binding upon the successors and permitted assigns of the undersigned.

This Irrevocable Proxy shall terminate, and be of no further force and effect, automatically upon the Expiration Date.

Dated: January __, 2009


		STOCKHOLDER



		[ ]

***** IRREVOCABLE PROXY ****

EXHIBIT B

NOTICE OF BENEFICIAL OWNERSHIP

[DATE]¹

The undersigned Stockholder (the “Stockholder”) of thinkorswim Group Inc., a Delaware corporation (the “Company”), hereby notifies TD AMERITRADE Holding Corporation, a Delaware corporation (“Parent”) that, as of the date hereof, such Stockholder beneficially owns the number of Shares set forth below.


STOCKHOLDER


[ ]

Shares beneficially owned as of the date hereof:

shares of Company Common Stock

shares of Company Common Stock issuable upon exercise of outstanding options


¹		Record Date of Company Stockholder Vote.

THINKORSWIM GROUP INC. SC 13D