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                                                                 Exhibit 4(bbbb)

                             SUB-ADVISORY AGREEMENT

                           RISK-MANAGED CORE PORTFOLIO
                        (A SERIES OF JANUS ASPEN SERIES)

      This SUB-ADVISORY AGREEMENT (the "Agreement") is entered into effective as
of the 1st day of July 2004, amended this 1st day of January 2006, by and
between JANUS CAPITAL MANAGEMENT LLC, a Delaware limited liability company
("Janus") and ENHANCED INVESTMENT TECHNOLOGIES, LLC, a Delaware limited
liability company ("INTECH").

      WHEREAS, Janus has entered into an Investment Advisory Agreement (the
"Advisory Agreement") with Janus Aspen Series, a Delaware statutory trust (the
"Trust") and an open-end, management investment company registered under the
Investment Company Act of 1940, as amended (the "1940 Act"), with respect to
Risk-Managed Core Portfolio, a series of the Trust (the "Fund") pursuant to
which Janus has agreed to provide investment advisory services with respect to
the Fund; and

      WHEREAS, INTECH is engaged in the business of rendering investment
advisory services and is registered as an investment adviser under the
Investment Advisers Act of 1940, as amended (the "Advisers Act"); and

      WHEREAS, Janus desires to retain INTECH to furnish investment advisory
services with respect to the Fund, and INTECH is willing to furnish such
services;

      NOW THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties agree as follows:

      1.    Duties of INTECH. Janus hereby engages the services of INTECH as
subadviser in furtherance of the Advisory Agreement. INTECH agrees to perform
the following duties, subject to the oversight of Janus and to the overall
control of the officers and the Board of Trustees (the "Trustees") of the Trust:

            (a) INTECH shall manage the investment operations of the Fund and
the composition of its investment portfolio, shall determine without prior
consultation with the Trust or Janus, what securities and other assets of the
Fund will be acquired, held, disposed of or loaned, and place orders for the
purchase or sale of such securities or other assets with brokers, dealers or
others, all in conformity with the investment objectives, policies and
restrictions and the other statements concerning the Fund in the Trust's trust
instrument, as amended from time to time (the "Trust Instrument"), bylaws and
registration statements under the 1940 Act and the Securities Act of 1933, as
amended (the "1933 Act"), the Advisers Act, the rules thereunder and all other
applicable federal and state laws and regulations, and the provisions of the
Internal Revenue Code of 1986, as amended (the "Code"), applicable to the Trust,
on behalf of the Fund, as a regulated investment company;

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            (b) INTECH shall cause its officers to attend meetings and furnish
oral or written reports, as the Trust or Janus may reasonably require, in order
to keep Janus, the Trustees and appropriate officers of the Trust fully informed
as to the condition of the investment portfolio of the Fund, the investment
decisions of INTECH, and the investment considerations which have given rise to
those decisions;

            (c) INTECH shall maintain all books and records required to be
maintained by INTECH pursuant to the 1940 Act, the Advisers Act, and the rules
and regulations promulgated thereunder, as the same may be amended from time to
time, with respect to transactions on behalf of the Fund, and shall furnish the
Trustees and Janus with such periodic and special reports as the Trustees or
Janus reasonably may request. INTECH hereby agrees that all records which it
maintains for the Fund or the Trust are the property of the Trust, agrees to
permit the reasonable inspection thereof by the Trust or its designees and
agrees to preserve for the periods prescribed under the 1940 Act and the
Advisers Act any records which it maintains for the Trust and which are required
to be maintained under the 1940 Act and the Advisers Act, and further agrees to
surrender promptly to the Trust or its designees any records which it maintains
for the Trust upon request by the Trust;

            (d) INTECH shall submit such reports relating to the valuation of
the Fund's assets and to otherwise assist in the calculation of the net asset
value of shares of the Fund as may reasonably be requested;

            (e) INTECH shall, on behalf of the Fund, exercise such voting
rights, subscription rights, rights to consent to corporate action and any other
rights pertaining to the Fund's assets that may be exercised, in accordance with
any policy pertaining to the same that may be adopted or agreed to by the
Trustees of the Trust, or, in the event that the Trust retains the right to
exercise such voting and other rights, to furnish the Trust with advice as may
reasonably be requested as to the manner in which such rights should be
exercised;

            (f) At such times as shall be reasonably requested by the Trustees
or Janus, INTECH shall provide the Trustees and Janus with economic, operational
and investment data and reports, including without limitation all information
and materials reasonably requested by or requested to be delivered to the
Trustees of the Trust pursuant to Section 15(c) of the 1940 Act, and shall make
available to the Trustees and Janus any economic, statistical and investment
services normally available to similar investment company clients of INTECH; and

            (g) INTECH will provide to Janus for regulatory filings and other
appropriate uses materially accurate and complete information relating to INTECH
as may be reasonably requested by Janus from time to time and, notwithstanding
anything herein to the contrary, INTECH shall be liable to Janus for all
damages, costs and expenses, including without limitation reasonable attorney's
fees (hereinafter referred to collectively as "Damages"), incurred by Janus as a
result of any material inaccuracies or omissions in such information provided by
INTECH to Janus, provided, however, that INTECH shall not be liable to the
extent that any Damages are based upon inaccuracies or omissions made in
reliance upon information furnished to INTECH by Janus.

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      2.    Further Obligations. In all matters relating to the performance of
this Agreement, INTECH shall act in conformity with the Trust's Trust
Instrument, bylaws and currently effective registration statements under the
1940 Act and the 1933 Act and any amendments or supplements thereto (the
"Registration Statements") and with the written policies, procedures and
guidelines of the Fund, and written instructions and directions of the Trustees
and Janus and shall comply with the requirements of the 1940 Act, the Advisers
Act, the rules thereunder, and all other applicable federal and state laws and
regulations. Janus agrees to provide to INTECH copies of the Trust's Trust
Instrument, bylaws, Registration Statement, written policies, procedures and
guidelines and written instructions and directions of the Trustees and Janus,
and any amendments or supplements to any of them at, or, if practicable, before
the time such materials become effective.

      3.    Obligations of Janus. Janus shall have the following obligations
under this Agreement:

            (a) To keep INTECH continuously and fully informed (or cause the
custodian of the Fund's assets to keep INTECH so informed) as to the composition
of the investment portfolio of the Fund and the nature of all of the Fund's
assets and liabilities from time to time;

            (b) To furnish INTECH with a certified copy of any financial
statement or report prepared for the Fund by certified or independent public
accountants and with copies of any financial statements or reports made to the
Fund's shareholders or to any governmental body or securities exchange;

            (c) To furnish INTECH with any further materials or information
which INTECH may reasonably request to enable it to perform its function under
this Agreement; and

            (d) To compensate INTECH for its services in accordance with the
provisions of Section 4 hereof.

      4.    Compensation. Janus shall pay to INTECH for its services under
this Agreement a fee, payable in United States dollars, at an annual rate of
0.26% of the average daily net assets of the Fund plus or minus one-half of any
performance adjustment paid to or incurred by Janus pursuant to the Advisory
Agreement between the Trust, on behalf of the Fund, and Janus. Fees paid to
INTECH shall be computed and accrued daily and payable monthly as of the last
day of each month during which or part of which this Agreement is in effect. For
the month during which this Agreement becomes effective and the month during
which it terminates, however, there shall be an appropriate proration of the fee
payable for such month based on the number of calendar days of such month during
which this Agreement is effective.

      5.    Expenses. INTECH shall pay all its own costs and expenses incurred
in rendering its service under this Agreement.

      6.    Representations of INTECH. INTECH hereby represents, warrants and
covenants to Janus as follows:

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            (a) INTECH: (i) is registered as an investment adviser under the
Advisers Act and will continue to be so registered for so long as this Agreement
remains in effect; (ii) is not prohibited by the 1940 Act or the Advisers Act
from performing the services contemplated by this Agreement; (iii) has met, and
will continue to meet for so long as this Agreement remains in effect, any other
applicable federal or state requirements, or the applicable requirements of any
regulatory or industry self-regulatory organization necessary to be met in order
to perform the services contemplated by this Agreement; (iv) has the legal and
corporate authority to enter into and perform the services contemplated by this
Agreement; and (v) will immediately notify Janus of the occurrence of any event
that would disqualify INTECH from serving as an investment adviser of an
investment company pursuant to Section 9(a) of the 1940 Act or otherwise, and of
the institution of any administrative, regulatory or judicial proceeding against
INTECH that could have a material adverse effect upon INTECH's ability to
fulfill its obligations under this Agreement.

            (b) INTECH has adopted a written code of ethics complying with the
requirements of Rule 17j-1 under the 1940 Act and will provide Janus with a copy
of such code of ethics, together with evidence of its adoption. Within 45 days
after the end of the last calendar quarter of each year that this Agreement is
in effect, the president or a vice president of INTECH shall certify to Janus
that INTECH has complied with the requirements of Rule 17j-1 during the previous
year and that there has been no violation of INTECH's code of ethics or, if such
a violation has occurred, that appropriate action was taken in response to such
violation. Upon the written request of Janus, INTECH shall permit Janus, its
employees or its agents to examine the reports required to be made to INTECH by
Rule 17j-1(c)(1) and all other records relevant to INTECH's code of ethics.

            (c) INTECH has provided Janus with a copy of its Form ADV as most
recently filed with the U.S. Securities and Exchange Commission ("SEC") and
will, promptly after filing any amendment to its Form ADV with the SEC, furnish
a copy of such amendment to Janus.

      7.    Representations of Janus. Janus hereby represents, warrants and
covenants to INTECH as follows:

            (a) Janus (i) is registered as an investment adviser under the
Advisers Act and will continue to be so registered for so long as this Agreement
remains in effect; (ii) is not prohibited by the 1940 Act or the Advisers Act
from fulfilling its obligations under this Agreement; (iii) has met, and will
continue to meet for so long as this Agreement remains in effect, any other
applicable federal or state requirements, or the applicable requirements of any
regulatory or industry self-regulatory organization necessary to be met in order
to fulfill its obligations under this Agreement; (iv) has the legal and
corporate authority to enter into and perform this Agreement; and (v) will
immediately notify INTECH of the occurrence of any event that would disqualify
Janus from serving as an investment adviser of an investment company pursuant to
Section 9(a) of the 1940 Act or otherwise, and of the institution of any
administrative, regulatory or judicial proceeding against Janus that could have
a material adverse effect upon Janus' ability to fulfill its obligations under
this Agreement.

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            (b) Janus has adopted a written code of ethics complying with the
requirements of Rule 17j-1 under the 1940 Act and will provide INTECH with a
copy of such code of ethics, together with evidence of its adoption.

            (c) Janus has provided INTECH with a copy of its Form ADV as most
recently filed with the U.S. Securities and Exchange Commission ("SEC") and
will, promptly after filing any amendment to its Form ADV with the SEC, furnish
a copy of such amendment to INTECH.

      8.    Term. This Agreement shall become effective as of the date
first set forth above and shall continue in effect until January 1, 2007, unless
sooner terminated in accordance with its terms, and shall continue in effect
from year to year thereafter only so long as such continuance is specifically
approved at least annually by (a) the vote of a majority of the Trustees of the
Trust who are not parties hereto or interested persons of the Trust, Janus or
INTECH, cast in person at a meeting called for the purpose of voting on the
approval of the terms of such renewal, and (b) either the Trustees of the Trust
or the affirmative vote of a majority of the outstanding voting securities of
the Fund. The annual approvals provided for herein shall be effective to
continue this Agreement from year to year if given within a period beginning not
more than ninety (90) days prior to January 1 of each applicable year,
notwithstanding the fact that more than three hundred sixty-five (365) days may
have elapsed since the date on which such approval was last given.

      9.    Termination. This Agreement may be terminated at any time,
without penalty, by the Trustees or by the shareholders of the Fund acting by
vote of at least a majority of its outstanding voting securities, provided in
any such case that 60 days' advance written notice of termination be given to
INTECH at its principal place of business. This Agreement may be terminated (i)
by Janus or by INTECH at any time, without penalty by giving 60 days' advance
written notice of termination to the other party, or (ii) by Janus or the Trust
without advance notice if INTECH becomes unable to discharge its duties and
obligations under this Agreement. In addition, this Agreement shall terminate,
without penalty, upon termination of the Advisory Agreement.

      10.   Assignment. This Agreement shall automatically terminate in the
event of its assignment.

      11.   Amendments. This Agreement may be amended by the parties only
in a written instrument signed by the parties to this Agreement and only if such
amendment is specifically approved (i) by a majority of the Trustees, including
a majority of the Trustees who are not interested persons (as that phrase is
defined in Section 2(a)(19) of the 1940 Act) of the Trust or Janus, INTECH or
their affiliates, and (ii) if required by applicable law, by the affirmative
vote of a majority of the outstanding voting securities of the Fund (as that
phrase is defined in Section 2(a)(42) of the 1940 Act).

      12.   Limitation on Personal Liability. All parties to this Agreement
acknowledge and agree that the Trust is a series trust and all debts,
liabilities, obligations and expenses incurred, contracted for or otherwise
existing with respect to a particular series shall be enforceable against

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the assets held with respect to such series only, and not against the assets of
the Trust generally or against the assets held with respect to any other series
and further that no Trustee, officer or holder of shares of beneficial interest
of the Trust shall be personally liable for any of the foregoing.

      13.   Limitation of Liability of INTECH. Janus will not seek to
hold INTECH, and INTECH shall not be, liable for any error of judgment or
mistake of law or for any loss arising out of any investment or for any act or
omission taken with respect to the Fund, except for willful misfeasance, bad
faith or gross negligence in the performance of its duties, or by reason of
reckless disregard of its obligations and duties hereunder and except to the
extent otherwise provided by law. As used in this section, "INTECH" shall
include any affiliate of INTECH performing services for the Fund contemplated
hereunder and directors, officers and employees of INTECH and such affiliates.

      14.   Activities of INTECH. The services of INTECH hereunder are
not to be deemed to be exclusive, and INTECH is free to render services to other
parties, so long as its services under this Agreement are not materially
adversely affected or otherwise impaired thereby. Nothing in this Agreement
shall limit or restrict the right of any director, officer or employee of INTECH
to engage in any other business or to devote his or her time and attention in
part to the management or other aspects of any other business, whether of a
similar or a dissimilar nature. It is understood that Trustees, officers and
shareholders of the Trust are or may become interested in INTECH as directors,
officers and shareholders of INTECH, that directors, officers, employees and
shareholders of INTECH are or may become similarly interested in the Trust, and
that INTECH may become interested in the Trust as a shareholder or otherwise.

      15.   Third Party Beneficiary. The parties expressly acknowledge
and agree that the Trust is a third party beneficiary of this Agreement and that
the Trust shall have the full right to sue upon and enforce this Agreement in
accordance with its terms as if it were a signatory hereto. Any oversight,
monitoring or evaluation of the activities of INTECH by Janus, the Trust or the
Fund shall not diminish or relieve in any way the liability of INTECH for any of
its duties and responsibilities under this Agreement.

      16.   Notices. Any notice or other communication required to be
given pursuant to this Agreement shall be deemed duly given if delivered
personally or by overnight delivery service or mailed by certified or registered
mail, return receipt requested and postage prepaid, or sent by facsimile
addressed to the parties at their respective addresses set forth below, or at
such other address as shall be designated by any party in a written notice to
the other party.

            (a)   To Janus at:

                  Janus Capital Management LLC
                  151 Detroit Street
                  Denver, Colorado  80206
                  Attention:  General Counsel
                  Phone:  (303) 333-3863
                  Fax:  (303) 316-5728

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            (b)   To INTECH at:

                  Enhanced Investment Technologies, LLC
                  2401 PGA Boulevard, Suite 200
                  Palm Beach Gardens, Florida 33410
                  Attention:  President
                  Phone:  (561) 775-1100
                  Fax:  (561) 775-1150

            (c)   To the Trust at:

                  Janus Aspen Series
                  151 Detroit Street
                  Denver, Colorado  80206
                  Attention:  General Counsel
                  Phone:  (303) 333-3863
                  Fax:  (303) 316-5728

      17.   Certain Definitions. The terms "vote of a majority of the
outstanding voting securities," "assignment," "approved at least annually," and
"interested persons" shall have the respective meanings specified in the 1940
Act, as now in effect or hereafter amended, and the rules and regulations
thereunder, subject to such orders, exemptions and interpretations as may be
issued by the SEC under the 1940 Act and as may be then in effect.

      18.   Governing Law. This Agreement shall be construed in
accordance with the laws of the State of Colorado (without giving effect to the
conflicts of laws principles thereof) and the 1940 Act. To the extent that the
applicable laws of the State of Colorado conflict with the applicable provisions
of the 1940 Act, the latter shall control.

      IN WITNESS WHEREOF, the parties have caused this Agreement to be executed
by their duly authorized officers designated below as of January 1, 2006.

                                       JANUS CAPITAL MANAGEMENT LLC

                                       By: /s/ David R. Martin
                                         ------------------------------
                                       Name:  David R. Martin
                                       Title: Executive Vice President and Chief
                                              Financial Officer

                                       ENHANCED INVESTMENT TECHNOLOGIES, LLC

                                       By: /s/ David E. Hurley
                                          ------------------------------
                                       Name:  David E. Hurley
                                       Title: Executive Vice President