Self-Regulatory Organizations; Chicago Stock Exchange, Inc.; Notice of Filing and Immediate Effectiveness of Proposed Rule Change to Extend the Pilot Program Relating to Individual Securities Circuit Breakers

Pursuant to Section 19(b)(1) of the Securities Exchange Act of 1934 (the “Act”) and Rule 19b-4 thereunder, notice is hereby given that on April 5, 2010, the Chicago Stock Exchange, Inc. (“CHX” or the “Exchange”) filed with the Securities and Exchange Commission (“Commission”) the proposed rule change as described in Items I and II below, which Items have been prepared by the Exchange. The Commission is publishing this notice to solicit comments on the proposed rule change from interested persons.

I. Self-Regulatory Organization's Statement of the Terms of Substance of the Proposed Rule Change

CHX proposes to amend its rules to extend the pilot program relating to individual securities circuit breakers. The text of this proposed rule change is available on the Exchange's Web site at ( http://www.chx.com ) and in the Commission's Public Reference Room.

II. Self-Regulatory Organization's Statement of the Purpose of, and Statutory Basis for, the Proposed Rule Change

In its filing with the Commission, the CHX included statements concerning the purpose of and basis for the proposed rule changes and discussed any comments it received regarding the proposal. The text of these statements may be examined at the places specified in Item IV below. The CHX has prepared summaries, set forth in sections A, B and C below, of the most significant aspects of such statements.

A. Self-Regulatory Organization's Statement of the Purpose of, and Statutory Basis for, the Proposed Rule Changes

1. Purpose

In June, 2010, CHX obtained Commission approval to amend Article 20, Rule 2 to create circuit breakers in individual securities on a pilot basis to end on December 10, 2010. Shortly thereafter, in September, the Commission approved another amendment to Article 20, Rule 2 to add securities included in the Russell 1000® Index (“Russell 1000”) and certain specified Exchange Traded Products (“ETP”) to the pilot rule. This program was subsequently extended until April 11, 2011. The proposed rule change merely extends the duration of the pilot program to the earlier of August 11, 2011 or the date on which a limit up/limit down mechanism to address extraordinary market volatility, if adopted, applies. Extending the pilot in this manner will allow it to continue until the limit up/limit down mechanism to address extraordinary market volatility, if adopted, applies.

2. Statutory Basis

The proposed rule change is consistent with Section 6(b)(5) of the Securities Exchange Act of 1934 (the “Act”), which requires the rules of an exchange to promote just and equitable principles of trade, to remove impediments to and perfect the mechanism of a free and open market and a national market system and, in general, to protect investors and the public interest. The proposed rule change also is designed to support the principles of Section 11A(a)(1) of the Act in that it seeks to assure fair competition among brokers and dealers and among exchange markets. The Exchange believes that the proposed rule meets these requirements in that it promotes uniformity across markets concerning decisions to pause trading in a security when there are significant price movements.

B. Self-Regulatory Organization's Statement of Burden on Competition

The Exchange does not believe that the proposed rule change will impose any burden on competition that is not necessary or appropriate in furtherance of the purposes of the Act.

C. Self-Regulatory Organization's Statement on Comments Regarding the Proposed Rule Changes Received From Members, Participants or Others

No written comments were either solicited or received.

III. Date of Effectiveness of the Proposed Rule Change and Timing for Commission Action

Because the foregoing proposed rule change does not: (i) Significantly affect the protection of investors or the public interest; (ii) impose any significant burden on competition; and (iii) become operative for 30 days from the date on which it was filed, or such shorter time as the Commission may designate if consistent with the protection of investors and the public interest, it has become effective pursuant to Section 19(b)(3)(A) of the Act and Rule 19b-4(f)(6) thereunder.

A proposed rule change filed under Rule 19b-4(f)(6) normally may not become operative prior to 30 days after the date of filing. However, Rule 19b-4(f)(6) permits the Commission to designate a shorter time if such action is consistent with the protection of investors and the public interest. The Exchange has requested that the Commission waive the 30-day operative delay.

The Commission has considered the Exchange's request to waive the 30-day operative delay. The Commission believes that waiving the 30-day operative delay is consistent with the protection of investors and the public interest, as it will allow the pilot program to continue uninterrupted, thereby avoiding the investor confusion that could result from a temporary interruption in the pilot program. For this reason, the Commission designates the proposed rule change to be operative upon filing.

At any time within 60 days of the filing of the proposed rule change, the Commission summarily may temporarily suspend such rule change if it appears to the Commission that such action is necessary or appropriate in the public interest, for the protection of investors, or otherwise in furtherance of the purposes of the Act. If the Commission takes such action, the Commission shall institute proceedings to determine whether the proposed rule change should be approved or disapproved.

IV. Solicitation of Comments

Interested persons are invited to submit written data, views, and arguments concerning the foregoing, including whether the proposed rule change, as amended, is consistent with the Act. Comments may be submitted by any of the following methods:

Electronic Comments

• Use the Commission's Internet comment form ( http://www.sec.gov/rules/sro.shtml ); or
• Send an e-mail to rule-comments@sec.gov. Please include File Number SR-CHX-2011-05 on the subject line.

Paper Comments

• Send paper comments in triplicate to Elizabeth M. Murphy, Secretary, Securities and Exchange Commission, 100 F Street, NE., Washington, DC 20549-1090.

All submissions should refer to File Number SR-CHX-2011-05. This file number should be included on the subject line if e-mail is used. To help the Commission process and review your comments more efficiently, please use only one method. The Commission will post all comments on the Commission's Internet Web site ( http://www.sec.gov/rules/sro.shtml ). Copies of the submission, all subsequent amendments, all written statements with respect to the proposed rule change that are filed with the Commission, and all written communications relating to the proposed rule change between the Commission and any person, other than those that may be withheld from the public in accordance with the provisions of 5 U.S.C. 552, will be available for Web site viewing and printing in the Commission's Public Reference Room, 100 F Street, NE., Washington, DC 20549, on official business days between the hours of 10 a.m. and 3 p.m. Copies of such filing also will be available for inspection and copying at the principal offices of the Exchange. All comments received will be posted without change; the Commission does not edit personal identifying information from submissions. You should submit only information that you wish to make available publicly.

All submissions should refer to File Number SR-CHX-2011-05, and should be submitted on or before May 3, 2011.