June 13, 2008

VIA EDGAR

Division of Investment Management
Securities and Exchange Commission
100 F Street, NE
Washington, DC  20549

Attn:    Valerie Lithotomos
         Sonny Oh

Re:      Security Equity Fund (File No. 811-01136)
         SBL Fund (File No. 811-02753) (the "Companies")

Dear Ms. Lithotomos and Mr. Oh:

On behalf of the Companies, we are transmitting for filing pursuant to Rule
14a-6 under the Securities Act of 1934 ("1934 Act") definitive proxy statements,
forms of proxies and other soliciting materials ("Proxy Materials") relating to
Special Meetings of Shareholders of Security Alpha Opportunity Fund and Series Z
(Alpha Opportunity Series) (together, the "Funds"), which are series of the
Companies. No fees are required with these filings.

We wish to respond by this letter to comments of the U.S. Securities and
Exchange Commission ("SEC") staff on the preliminary Proxy Materials filed
pursuant to Rule 14a-6 under the 1934 Act on May 29, 2008. The SEC staff's
comments were conveyed orally by Valerie Lithotomos and Sonny Oh at the Division
of Investment Management via separate telephone conferences with Julien
Bourgeois at Dechert LLP on June 9, 2008 and by Ms. Lithotomos and Richard Forti
on June 11, 2008. Throughout this letter, capitalized terms have the same
meaning as in the Proxy Materials, unless otherwise noted. A summary of the SEC
staff's comments, followed by the responses of the Funds, is set forth below:

1.   Comment: Please confirm that the proxy statement properly reflects all
     defined terms.

     Response: We have reviewed and revised the proxy statement to make the
     necessary changes to the defined terms.

2.   Comment: On page 2 of the proxy statements under the heading "Changes to
     the Principal Investment Strategies," please disclose that shareholder
     approval is not required to institute the changes to the principal
     investment strategies.

     Response: We have implemented the requested change to the disclosure.





3.   Comment: Please clarify at the beginning of the proxy statement why
     shareholder approval is not needed with respect to the changes to the
     Mainstream Sub-Advisory Agreement.

     Response: We have implemented the requested change to the disclosure.

4.   Comment: Under the headings titled "Comparison of the Current Advisory
     Agreement with the Amended Advisory Agreement" and "Comparison of the
     Current Management Agreement with the Amended Management Agreement" on page
     3 of the proxy statements, please confirm when the Current Advisory
     Agreement and Current Management Agreement were last approved by
     shareholders.

     Response: We have revised the disclosure to indicate the appropriate date
     the Current Advisory Agreement and Current Management Agreement were last
     approved by shareholders.

5.   Comment: Under the discussion of the fee structure under the Current and
     Amended Advisory/Management Agreements, please discuss that each Fund could
     pay the Investment Manager the minimum advisory fee even though the
     Investment Manager had positive performance in the sub-portfolio it manages
     if overall Fund performance significantly underperforms the S&P 500 Index
     due to the level of performance of the Fund.

     Response: We have implemented the requested change to the disclosure.

6.   Comment: On page 5 of the proxy statements, please include additional
     information in the table disclosing the total annual fees that the
     Investment Manager would earn at various levels of investment performance
     of the Funds and the S&P 500 to further clarify the functioning of the
     Fund's current performance-based fee arrangement.

     Response: The tables in the proxy statements appear in the Funds' current
     prospectuses, which have been reviewed by, and discussed with, the SEC
     staff in the past. We believe that any changes to the tables in the proxy
     statement could be potentially confusing to investors, because they would
     not match the disclosure in the Funds' current registration statements. As
     a result, no change has been made in response to this comment.

7.   Comment: On page 6 of the proxy statements in the tables comparing the
     Funds' advisory/management fees as calculated under the terms of the
     Current Advisory/Management Agreement and the Amended Advisory/Management
     Agreement, please consider also providing the fees paid for last 5 fiscal
     years. In addition, please provide the differences in percentage terms
     between the values provided under the Current and Amended
     Advisory/Management Agreements as required by Item 22(c)(9)(iii).

     Response: With respect to the first part of the comment from the staff, we
     believe that the tables are responsive to the requirements set forth under
     Schedule 14A and related proxy rules. We have implemented the second
     request by adding the percentage differences between the fees paid under
     Current and Amended Advisory/Management Agreements as required by Item
     22(c)(9)(iii).

8.   Comment: In the proxy statement for Security Alpha Opportunity Fund, the
     staff believes that applicable guidance requires that the fee table lines
     titled "Distribution (12b-1) fees" on pages 6 and 7 of the proxy statement
     should be titled "Distribution (12b-1) and service fees."

     Response: We have implemented the requested change to the disclosure.


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9.   Comment: The staff noted that the Investment Manager is entitled to recoup
     previously waived fees and expenses under the disclosed expense limitation
     arrangement. Please indicate whether the Board of the Funds must further
     approve these recoupments.

     Response: The Board is not required to further approve recoupments pursuant
     to the Funds' fee waiver agreement.

10   Comment: Please confirm that the "Evaluation by the Board" starting on page
     7 of the Series Z (Alpha Opportunity Series) proxy statement and page 8 of
     the Security Alpha Opportunity Fund proxy statement is responsive to the
     Item 22(c)(11) of Schedule 14A with respect to the approval of the
     Agreements.

     Response: The Funds believe that the disclosure is responsive to Item
     22(c)(11) of Schedule 14A and no additional disclosure is required.

11.  Comment: Please disclose what happens if the proposals in the proxy
     statements are not approved by shareholders.

     Response: We have implemented the requested change to the disclosure.

12.  Comment: Please remove the first sentence in the second paragraph under
     "Shareholder Reports" on page 11 of the Series Z (Alpha Opportunity Series)
     proxy statement and page 13 of the Security Alpha Opportunity Fund proxy
     statement.

     Response: We have implemented the requested change to the disclosure.

13.  Comment: Please confirm that additional disclosure is not needed to respond
     to Items 22(c)(6) and 22(c)(7) of Schedule 14A.

     Response: The Funds believe that no additional disclosure is needed to
     respond to Items 22(c)(6) and 22(c)(7) of Schedule 14A.

14.  Comment: Please update Exhibit E in each proxy statement before filing the
     definitive proxy statement.

     Response: We have updated Exhibit E for the definitive proxy statement
     filing.

15.  Comment: Please explain the initial purpose of the performance-based
     investment advisory/management fee under the Current Advisory/Management
     Agreements for the Funds and discuss the circumstances that have led each
     Fund's Board to determine that it should now be eliminated. Please confirm
     that there is clear disclosure explaining that, depending on the
     performance of the Funds and variations in net assets of the Funds, the
     proposed fixed fee structure could in fact result in higher fees than under
     the current performance-based fee structure. Also, please disclose the
     benefits of a performance-based fee arrangement and that these benefits
     would not exist under the proposed fixed fee.

     Response: The performance-based investment advisory/management fees
     originated with a proposal by the Investment Manager, that each Board
     consider a performance-based component to the fee. In the proposal, the
     Investment Manager explained that


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     Mainstream's clients were primarily unregistered funds and accounts, and
     these clients paid fees based on performance.

     In determining whether to eliminate the performance-based component of the
     investment advisory/management fee, the Board noted that a fixed fee is
     more common among registered investment companies and provides for a level
     of Fund expenses that is more predictable. The Board noted that the
     performance-based component was not received as well in the marketplace as
     anticipated and that, despite a competitive performance track record, the
     Funds have not attracted the assets that were originally anticipated. In
     addition, the performance-based component of the current fee structure
     generally led to higher investment advisory/management fees paid by the
     Funds (the new investment advisory/management fees proposed in the Proxy
     Materials would be equal to the lowest level of advisory/management
     annualized fees payable under the Current Advisory/Management Agreements
     for the Funds). It was also noted that the performance-based fee is
     difficult to adapt in a multi-manager structure when the investment
     advisory/management fee is used to pay several sub-advisers.

     We confirm that the disclosure explaining that the proposed fixed fee
     arrangement could, in theory, result in higher fees than under the current
     performance-based fee structure appears in the Proxy Materials (see
     discussion under the sections titled "Comparison of the Fee Structures
     under the Advisory Agreements" and "Comparison of the Fee Structures under
     the Management Agreements" on page 6 of the proxy statements). We have also
     implemented the requested change to the disclosure by adding the following
     under the sections titled "Comparison of the Fee Structures under the
     Advisory Agreements" and "Comparison of the Fee Structures under the
     Management Agreements" on page 6 of proxy statements:

          Fee arrangements with a performance-based component, such as the fee
          arrangement in place under the Current Advisory/Management Agreements,
          are intended to create an incentive for an investment manager to
          generate positive performance for a fund. A fixed-fee arrangement does
          not have the same direct incentive (although an investment manager
          remains subject to the same duties).

16.  Comment: The staff notes its prior position in Factors to be Considered in
     Connection with Investment Company Advisory Contracts Containing Incentive
     Arrangements, Investment Advisers Act Release No. 315 (Apr. 6, 1972) (the
     "1972 Release"). Please discuss whether the termination and replacement of
     the investment advisory arrangement will include a "winding down" period,
     as discussed in the 1972 Release.

     Response: In the 1972 Release, the SEC indicated that an investment
     adviser's termination and replacement of an investment advisory arrangement
     that includes a performance-based component with a fixed fee rate could
     raise fairness concerns. In particular, the SEC stated that it was
     concerned that an investment adviser could identify situations where fund
     performance was below its benchmark (so a negative performance adjustment
     would be in effect) and attempt to renegotiate the advisory contract to
     provide for an fixed fee that would be higher that what it would have
     earned under the original contract.

     The Funds believe that the present facts are distinguishable from those
     contemplated in the 1972 Release for the several reasons. The 1972 Release
     states that the cancellation of a "rolling" performance fee could be unfair
     to the investment company and not that it


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     inherently raises a "fairness" concern. In the present case, the new
     proposed fees are lower than the fees expected to be payable by the Funds
     until the end of the current performance period (based on recent past
     performance). The proposed fixed investment advisory/management fee rate is
     equal to the minimum annualized fee rate payable under the Current
     Advisory/Management Agreements.1 Consequently, the proposed fees are
     expected benefit the Funds and their shareholders and not be unfair to
     them.

     Also, the SEC position about "winding down" periods predates the adoption
     of Rules 205-1 and 205-2 under the Advisers Act, which apply to the Funds'
     current performance-based fee arrangements.2 Neither Section 205 under the
     Advisers Act nor Rules 205-1 or 205-2 thereunder explicitly require
     "winding down" periods. Furthermore, Section 15 of the 1940 Act, which
     regulates the Funds' current investment advisory arrangements, permits a
     change of investment advisory fee at any time (including an increase of
     fees) subject to the provisions of Section 15, such as the requirement to
     obtain Board and shareholder approval. In the Funds' case, the Funds will
     fully comply with Section 15's requirements. Notably, each Fund's Board has
     reviewed and approved the proposed arrangement in light of its fiduciary
     duties, and each Amended Advisory/Management Agreement with the Investment
     Manager will be subject to approval by the Fund's shareholders before it
     becomes effective. The Proxy Materials fully disclose the functioning of
     the current performance-based fees and how these compare to a fixed fee.

     Finally, the Funds' directors were aware of the positions taken in the 1972
     Release on "winding down" periods when they approved the new fee
     arrangements subject to shareholder approval. They were advised by Fund
     counsel and independent legal counsel during their consideration.

17.  Comment: Please include standard Tandy representation language in your
     transmittal letter for your upcoming filing.

     Response: Each Fund agrees to make the following representations:

          o    the Fund is responsible for the adequacy and accuracy of the
               disclosure in the filing;

          o    the staff comments or changes to disclosure in response to staff
               comments in the filing reviewed by the staff do not foreclose the
               SEC from taking any action with respect to the filing; and

          o    the Fund may not assert staff comments as a defense in any
               proceeding initiated by the SEC under the federal securities
               laws.

                                    *  *  *



--------------------
1    It is worthy of note that each Fund's recent performance is superior to the
     investment record of its benchmark index and each Fund has increased its
     asset size. Those elements would result in positive performance adjustments
     (at least in the short-term).

2    The 1972 Release was issued in April 1972. Rule 205-1 was adopted on August
     8, 1972 (see Release No. IA-327 (Aug. 8, 1972)) and Rule 205-2 was adopted
     on November 10, 1972 (see Release No. IA-347 (Nov. 10, 1972)).


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Please call Julien Bourgeois at Dechert LLP at 202.261.3451 with any questions
or comments regarding this letter, or if he may assist you in any way.

                                         Very truly yours,


                                     /s/ Chris Swickard
                                         ---------------------------
                                         Chris Swickard
                                         Assistant Secretary
                                         Security Investors, LLC


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