4.950% Senior Notes due 2014

Exhibit 4.21

THE CHARLES SCHWAB CORPORATION, as Issuer

and

THE BANK OF NEW YORK MELLON TRUST COMPANY, N.A., as Trustee

4.950% Senior Notes due 2014

First Supplemental Indenture

Dated as of June 5, 2009

to

Senior Indenture dated as of June 5, 2009

Table of Contents

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FIRST SUPPLEMENTAL INDENTURE, dated as of June 5, 2009 (“ Supplemental Indenture ”), to the Indenture dated as of June 5, 2009 (as amended, modified or supplemented from time to time in accordance therewith, other than with respect to a particular series of debt securities, the “ Base Indenture ” and, as amended, modified and supplemented by this Supplemental Indenture, the “ Indenture ”), by and among THE CHARLES SCHWAB CORPORATION (the “ Company ”), and THE BANK OF NEW YORK MELLON TRUST COMPANY, N.A., as trustee (the “ Trustee ”).

Each party agrees as follows for the benefit of the other party and for the equal and ratable benefit of the Holders of the Notes:

WHEREAS, the Company has duly authorized the execution and delivery of the Base Indenture to provide for the issuance from time to time of senior debt securities to be issued in one or more series as provided in the Base Indenture;

WHEREAS, the Company has duly authorized the execution and delivery, and desires and has requested the Trustee to join it in the execution and delivery, of this Supplemental Indenture in order to establish and provide for the issuance by the Company of a series of Securities designated as its 4.950% Senior Notes due 2014 (the “ Notes ”), on the terms set forth herein;

WHEREAS, Article IX of the Base Indenture provides that a supplemental indenture may be entered into by the parties for such purpose provided certain conditions are met;

WHEREAS, the conditions set forth in the Base Indenture for the execution and delivery of this Supplemental Indenture have been met; and

WHEREAS, all things necessary to make this Supplemental Indenture a valid and legally binding agreement of the parties, in accordance with its terms, and a valid and legally binding amendment of, and supplement to, the Base Indenture with respect to the Notes have been done;

NOW, THEREFORE:

ARTICLE I

DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION

Section 1.01 Definitions . Capitalized terms used herein and not otherwise defined herein have the meanings assigned to them in the Base Indenture. The words “herein”, “hereof” and “hereby” and other words of similar import used in this Supplemental Indenture refer to this Supplemental Indenture as a whole and not to any particular section hereof.

As used herein, the following terms have the specified meanings:

“ Additional Notes ” has the meaning specified in Section 3.04 of this Supplemental Indenture.

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“ Base Indenture ” has the meaning specified in the recitals of this Supplemental Indenture.

“ Business Day ” means any day other than (i) a Saturday or Sunday or (ii) a day on which banking institutions in Los Angeles, California or New York, New York are authorized or obligated by law or executive order to close.

“ Company ” has the meaning specified in the recitals of this Supplemental Indenture.

“ Comparable Treasury Issue ” means the United States Treasury security or securities selected by the Quotation Agent as having an actual or interpolated maturity comparable to the remaining term of the Notes to be redeemed that would be utilized, at the time of selection and in accordance with customary financial practice, in pricing new issues of corporate debt securities of a comparable maturity to the remaining term of such Notes.

“ Comparable Treasury Price ” means, with respect to any Redemption Date pursuant to Section 4.01 of this Supplemental Indenture, (A) the arithmetic average of the Reference Treasury Dealer Quotations for such Redemption Date, after excluding the highest and lowest such Reference Treasury Dealer Quotations, or (B) if the Quotation Agent obtains fewer than four such Reference Treasury Dealer Quotations, the arithmetic average of all such quotations for such Redemption Date.

“ Depositary ” means The Depository Trust Company or such other Depositary designated by the Company from time to time.

“ Initial Notes ” has the meaning set forth in Section 3.01(b) of this Supplemental Indenture.

“ Interest Payment Date ” has the meaning set forth in Section 3.01(d) of this Supplemental Indenture.

“ISIN” means International Securities Identifying Number.

“ Notes ” has the meaning specified in the recitals of this Supplemental Indenture.

“ Permitted Liens ” has the meaning set forth in Section 5.01 of this Supplemental Indenture.

“ Primary Treasury Dealer ” means a primary U.S. Government securities dealer in the United States.

“ Quotation Agent ” means the Reference Treasury Dealer that is selected by the Company in connection with an optional redemption pursuant to Article IV hereof to act as Quotation Agent in addition to acting as a Reference Treasury Dealer; provided , however , that if such Reference Treasury Dealer ceases to be a Primary Treasury Dealer, the Company will substitute another Primary Treasury Dealer.

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“ Redemption Date ,” when used with respect to any Note, means the date specified for redemption by the Company.

“ Redemption Price ” means, when used with respect to any Note to be redeemed, the price at which it is to be redeemed pursuant to this Supplemental Indenture.

“ Reference Treasury Dealer ” means (i) J.P. Morgan Securities Inc. (or its successor) or any affiliate that is a Primary Treasury Dealer, (ii) UBS Securities LLC (or its successor) or any affiliate that is a Primary Treasury Dealer, and (iii) up to two other Primary Treasury Dealers that are selected by the Company; provided , however , that if any of the foregoing or their affiliates shall cease to be a Primary Treasury Dealer, the Company will substitute therefor another Primary Treasury Dealer.

“ Reference Treasury Dealer Quotations ” means, with respect to each Reference Treasury Dealer and any Redemption Date, the arithmetic average, as determined by the Quotation Agent, of the bid and asked prices for the Comparable Treasury Issue (expressed in each case as a percentage of its principal amount) quoted in writing to the Quotation Agent by such Reference Treasury Dealer at 3:30 p.m., New York City time, on the third Business Day preceding such Redemption Date.

“ Regular Record Date ” has the meaning set forth in Section 3.01(d) of this Supplemental Indenture.

“ Supplemental Indenture ” has the meaning specified in the recitals of this Supplemental Indenture.

“ Treasury Rate ” means, with respect to any Redemption Date pursuant to Section 4.01 of this Supplemental Indenture, the rate per annum equal to the semiannual equivalent yield to maturity or interpolated (on a day count basis) of the Comparable Treasury Issue, assuming a price for the Comparable Treasury Issue (expressed as a percentage of its principal amount) equal to the Comparable Treasury Price for such Redemption Date.

“ Voting Securities ” has the meaning specified in Section 5.01 of this Supplemental Indenture.

Section 1.02 Conflicts with Base Indenture . In the event that any provision of this Supplemental Indenture limits, qualifies or conflicts with a provision of the Base Indenture, such provision of this Supplemental Indenture shall control.

ARTICLE II

FORM OF NOTES

Section 2.01 Form of Notes . The Notes shall be substantially in the form of Exhibit A hereto which is hereby incorporated in and expressly made a part of this Indenture.

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ARTICLE III

THE NOTES

Section 3.01 Amount; Series; Terms . (a) There is hereby created and designated a series of Securities under the Base Indenture: the title of the Notes shall be “4.950% Senior Notes Due 2014”. The changes, modifications and supplements to the Base Indenture effected by this Supplemental Indenture shall be applicable only with respect to, and govern the terms of, the Notes and shall not apply to any other series of Securities that may be issued under the Base Indenture unless a supplemental indenture with respect to such other series of Securities specifically incorporates such changes, modifications and supplements.

(b) The aggregate principal amount of Notes that initially may be authenticated and delivered under this Supplemental Indenture shall be limited to $750,000,000 (the “ Initial Notes ”), subject to increase as set forth in Section 3.04.

(c) The Stated Maturity of the Notes shall be June 1, 2014. The Notes shall be payable and may be presented for payment, redemption, registration of transfer and exchange, without service charge, at the Corporate Trust Office.

(d) The Notes shall bear interest at the rate of 4.950% per annum from and including June 5, 2009, or from the most recent date to which interest has been paid or duly provided for, as further provided in the form of Note annexed hereto as Exhibit A. Interest shall be computed on the basis of a 360-day year composed of twelve 30-day months. The dates on which such interest shall be payable (each, an “ Interest Payment Date ”) shall be June 1 and December 1 of each year, beginning on December 1, 2009, and the “ Regular Record Date ” for any interest payable on each such Interest Payment Date shall be the close of business on the immediately preceding May 15 and November 15, respectively, whether or not a Business Day. Interest will be payable to the Holder of record on the Regular Record Date, provided, however, interest payable on the Stated Maturity will be paid to the person to whom the principal will be payable.

(e) If any Interest Payment Date or the Stated Maturity of the Notes is not a Business Day, then the related payment of interest or principal payable, as applicable, on such date will be paid on the next succeeding Business Day with the same force and effect as if made on such Interest Payment Date or Stated Maturity and no further interest will accrue as a result of such delay.

(f) The Notes will be issued in the form of one or more Global Securities, duly executed by the Company and authenticated by the Trustee as provided in Section 3.03 and the Base Indenture and deposited with the Trustee as custodian for the Depositary or its nominee.

(g) Initially, the Trustee will act as Paying Agent. The Company may change any Paying Agent without notice to the Holders.

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Section 3.02 Denominations . The Notes shall be issuable only in registered form without coupons and only in denominations of $1,000 and any multiple of $1,000 in excess thereof.

Section 3.03 Execution, Authentication, Delivery and Dating . The Notes shall be executed on behalf of the Company by its Chairman of the Board, its Vice Chairman of the Board, its Chief Executive Officer (or any Co-Chief Executive Officer if the title is allocated to more than one person), its President, its Chief Financial Officer or its Treasurer, and attested by its Secretary or one of its Assistant Secretaries. The signature of any of these officers on the Notes may be manual or facsimile and shall not be required to be under the Company’s corporate seal.

Notes bearing the manual or facsimile signatures of individuals who were at any time the proper officers of the Company shall bind the Company, notwithstanding that such individuals or any of them have ceased to hold such offices prior to the authentication and delivery of such Notes or did not hold such offices at the date of such Notes.

Pursuant to a Company Order, the Trustee shall authenticate for original issue Notes in an aggregate principal amount specified in the Company Order. The Trustee shall be entitled to receive an Officer’s Certificate and an Opinion of Counsel of the Company that it may reasonably request in connection with such authentication of Notes. Such Company Order shall specify the amount of Notes to be authenticated and the date on which the original issue of Notes is to be authenticated.

Each Note shall be dated the date of its authentication.

No Note shall be entitled to any benefit under this Indenture or be valid or obligatory for any purpose unless there appears on such Note a certificate of authentication substantially in the form provided for in the Base Indenture executed by the Trustee by manual or facsimile signature, and such certificate upon any Note shall be conclusive evidence, and the only evidence, that such Note has been duly authenticated and delivered hereunder.

Section 3.04 Additional Notes . The Company may, from time to time, subject to compliance with any other applicable provisions of this Indenture, without notice to or consent of the Holders of the Notes, create and issue pursuant to this Indenture additi