<PAGE>
                                                                [EXHIBIT (4)(o)]

                      MERRILL LYNCH LIFE INSURANCE COMPANY

              GUARANTEED MINIMUM WITHDRAWAL BENEFIT ("GMWB") RIDER


This Rider is part of the Contract to which it is attached (the "Base Contract")
and is subject to all the terms and conditions of the Base Contract. The
provisions of this Rider control over any contrary provisions of the Base
Contract.

This Rider is available only if, on the GMWB Effective Date, the Owner (and
Co-Owner, if any) is not younger than the Minimum Age for GMWB Rider and is not
older than the Maximum Age for GMWB Rider. The GMWB Effective Date and the
Minimum Age and Maximum Age for the GMWB Rider are shown on the GMWB Rider page
of the Contract Schedule ("GMWB Rider Schedule").

If the Owner is a non-natural person, all references to Owner shall mean
Annuitant. As described on the GMWB Rider Schedule, restrictions may apply to
Owners and Annuitants.

RIGHT TO CANCEL RIDER: As described on the GMWB Rider Schedule, You may cancel
this Rider to be effective on any of the Allowable GMWB Cancellation Dates by
notification acceptable to Us.

RIGHT TO ADD RIDER: As described on the GMWB Rider Schedule, if this Rider has
been cancelled, You may re-elect it to be effective on any of the subsequent
Allowable GMWB Addition Dates by notification acceptable to Us. Availability of
this Rider and its provisions are subject to the terms and conditions in effect
at the time of each subsequent Allowable GMWB Addition Date.

WAIVER OF CONTRACT PROVISIONS: As described on the GMWB Rider Schedule, certain
Contract provisions will be waived while this Rider is in effect.

ALLOCATION GUIDELINES AND RESTRICTIONS: As described on the GMWB Rider Schedule,
Allocation Guidelines and Restrictions will apply and We may periodically
rebalance Your Account Value while this Rider is in effect.

GUARANTEED LIFETIME AMOUNT (GLA): This Rider guarantees that You may receive up
to the GLA each year during Your lifetime (or, if there are Co-Owners, until the
death of the second Owner).

Your GLA is determined by multiplying the applicable Lifetime Income Percentage
by the GMWB Base. The Lifetime Income Percentage and GMWB Base and how each is
determined are described on the GMWB Rider Schedule

Withdrawals which cause the cumulative amount withdrawn in any Contract Year to
be greater than the GLA will reduce the GMWB Base, possibly to zero.

If the Account Value is reduced to zero as a result of either a withdrawal or
the deduction of fees and/or charges and the resulting GMWB Base is greater than
zero, then an Annuity Date will be established and GLA payments will be made
each year as described under GMWB Settlement on the GMWB Rider Schedule.

Any Ownership change that does not result in termination of this Rider may
result in a change to the Lifetime Income Percentage. Any change in the Lifetime
Income Percentage or the GMWB Base will result in a corresponding change to Your
GLA.


                                      -1-


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WAIVER OF SURRENDER CHARGE: As described on the GMWB Rider Schedule, any
Surrender Charge that would otherwise apply to all or a portion of a withdrawal
made while this Rider is in effect may be waived.

PREMIUM LIMITATION: As described on the GMWB Rider Schedule, We may limit or not
accept additional Premiums while this Rider is in effect.

BENEFIT AVAILABLE ON MATURITY DATE: As described on the GMWB Rider Schedule, if
the Maturity Date occurs while this Rider is in effect, We will make the GLA
available each year through lifetime annuity payments as described on the GMWB
Rider Schedule.

GMWB CHARGE: The current and maximum GMWB Charge Percentage, how the charge is
determined, and when and how it is collected are described on the GMWB Rider
Schedule. The current GMWB Charge may change but it will never exceed the
maximum GMWB Charge.

TERMINATION:  This Rider will terminate upon the earliest of:

  (i)   a withdrawal that reduces the GMWB Base to zero; or
  (ii)  a change of Owner resulting in termination as described under Change
        of Owner on the GMWB Rider Schedule; or
  (iii) cancellation of this Rider in accordance with the Right to Cancel
        Rider provision; or
  (iv)  establishment of an Annuity Date when the Account Value has been
        reduced to zero and the GMWB Base is greater than zero as described
        under Guaranteed Lifetime Amount; or
  (v)   application of all of the Annuity Value to an Annuity Option on the
        Annuity Date; or
  (vi)  receipt of Due Proof of Death of the Owner (the first Owner to die if
        this Contract has Co-Owners) unless at that time this Rider is
        available under the Base Contract and an Eligible Spousal Beneficiary
        continues the Base Contract and qualifies for continuation of this
        Rider; or
 (vii)  termination of the Base Contract.

All benefits and charges associated with this Rider will cease after the
effective date of termination.


                             MERRILL LYNCH LIFE INSURANCE COMPANY



                             By:       /s/ Lori M. Salvo
                                 --------------------------------
                                            Secretary




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<PAGE>

                          CONTRACT SCHEDULE (CONTINUED)
                                            Contract Number:     [%999999999]

GMWB RIDER SCHEDULE

GMWB EFFECTIVE DATE:                   [October 1, 2005]

MINIMUM AGE FOR GMWB RIDER:             [60]

MAXIMUM AGE FOR GMWB RIDER:             [80]

ALLOWABLE GMWB CANCELLATION DATES:      each 3rd Contract Anniversary, provided
                                        We receive written notification at Our
                                        Service Center no earlier than 90 days
                                        but at least 3 days prior to such GMWB
                                        Cancellation Date.

ALLOWABLE GMWB ADDITION DATES:          each 3rd Contract Anniversary, provided
                                        We receive written notification at Our
                                        Service Center no earlier than 90 days
                                        but at least 3 days prior to such GMWB
                                        Addition Date.


RESTRICTIONS ON OWNERS:
                Only spouses may be Co-Owners. If there are Co-Owners, they also
                must be Joint Annuitants.

RESTRICTIONS ON ANNUITANTS:
                If the Owner is an individual natural person, then the Annuitant
                must be the Owner. Only spouses may be Joint Annuitants. If
                there are Joint Annuitants, they also must be Co-Owners.

WAIVER OF CONTRACT PROVISIONS:
                The following Contract Provisions are waived while this Rider is
                in effect:

                    1.   the Inactive Contract provision in the General
                         Provisions section of the Base Contract; and

                    2.   the Minimum Surrender Value after a partial
                         withdrawal requirement in the Withdrawals
                         Requirements and Limitations section of the
                         Contract Schedule, except if You request a
                         withdrawal resulting in an Excess Withdrawal (as
                         described in the GMWB Base section of the GMWB
                         Rider Schedule).


ALLOCATION GUIDELINES AND RESTRICTIONS:

                You must participate in a quarterly Rebalancing Program and
                provide Us with written instructions that comply with the
                following:

                    (1)  You must allocate at least [40%], but not more than
                         [70%] of Your total allocations among subaccounts
                         in the following Investment Categories:

                               Large Cap
                               Mid Cap
                               Small Cap
                               International


                    (2)  You must allocate no more than [40%] of Your total
                         allocations among the following Investment
                         Categories:

                               Small Cap
                               International
                               Alternative
                               Money Market


                                      -3-
<PAGE>
                          CONTRACT SCHEDULE (CONTINUED)
                                            Contract Number:     [%999999999]

GMWB RIDER SCHEDULE (CONTINUED)

                    (3)  You must allocate the remaining amounts among the
                         other Investment Categories so Your total
                         allocations equal 100%.

                    (4)  You must choose a periodic Rebalancing Date from
                         the 1st through the 28th day of the month.

                    (5)  You must  schedule  Your first  Rebalancing  Date
                         to begin within 95 days from the GMWB  Effective
                         Date.

                    (6)  You agree to furnish new allocation instructions
                         that comply with (1) - (3) above prior to any
                         future closure or elimination of a subaccount in
                         which You are invested.

                You may request to change Your instructions while this Rider is
                in effect provided that each request complies with (1) - (4)
                above.

                On a GMWB Addition Date and on each quarterly Rebalancing Date
                thereafter, We automatically reallocate Your Account Value to
                maintain the percentage allocation among the subaccounts that
                You have selected.

                You must allocate any additional Premiums in accordance with the
                subaccounts and percentages You have selected.

                You may request to transfer among subaccounts while this Rider
                is in effect provided that each request results in an allocation
                of Your Account Value that complies with (1) and (2) above as of
                the end of the last Valuation Period preceding receipt of Your
                request.

                Only pro-rata withdrawal requests affecting all subaccounts in
                which You are invested will be accepted while this Rider is in
                effect.

LIFETIME INCOME PERCENTAGE:
                The initial Lifetime Income Percentage set forth below is based
                upon the age of the Owner (or the younger Owner if there are
                Co-Owners) on the date of the first withdrawal on or after the
                GMWB Effective Date.

<TABLE>
<CAPTION>
                           Age of (Younger) Owner when              Lifetime
                         First Withdrawal is taken on or             Income
                            after GMWB Effective Date              Percentage
                         -------------------------------           ----------
<S>                      <C>                                       <C>
                                    60 - 64                          [4.5%]
                                    65 - 69                          [5.0%]
                                    70 - 74                          [5.5%]
                                    75 - 79                          [6.0%]
                                      80+                            [7.0%]
</TABLE>


                The Lifetime Income Percentage will be redetermined on the
                effective date of a change of Owner acceptable to Us, in
                accordance with the percentages then in effect.

                                      -4-
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                          CONTRACT SCHEDULE (CONTINUED)
                                            Contract Number:     [%999999999]

GMWB RIDER SCHEDULE (CONTINUED)

GMWB BASE:

                THE GMWB BASE IS USED SOLELY TO DETERMINE THE GUARANTEED
                LIFETIME AMOUNT (GLA) AND THE GMWB CHARGE. THE GMWB BASE DOES
                NOT ESTABLISH OR GUARANTEE AN ACCOUNT VALUE, SURRENDER VALUE,
                MINIMUM DEATH BENEFIT OR MINIMUM RETURN FOR ANY INVESTMENT
                OPTION.

                (1) ON THE GMWB EFFECTIVE DATE:

                    If the GMWB Effective Date is the Contract Date, the GMWB
                    BASE is the Initial Premium. If the GMWB Effective Date is
                    an Allowable GMWB Addition Date, the GMWB BASE is the
                    Contract Value on the GMWB Effective Date.

                (2) PRIOR TO THE FIRST WITHDRAWAL AFTER THE GMWB EFFECTIVE DATE:

                    The GMWB BASE is equal to GMWB Maximum Anniversary Value
                    (MAV) Base.

                              GMWB MAV BASE: The GMWB MAV Base is equal to the
                              greatest of the anniversary values. An anniversary
                              value is equal to the sum of (i) plus (ii) where:

                                   (i)  is the GMWB Base on the GMWB Effective
                                        Date and is the Contract Value on each
                                        Contract Anniversary thereafter; and
                                   (ii) is the sum of all Additional Premiums
                                        since that date.

                             We will calculate an anniversary value on the GMWB
                             Effective Date and on each Contract Anniversary
                             thereafter through the earlier of the date You make
                             Your first withdrawal on or after the GMWB
                             Effective Date, and the [10th] Contract Anniversary
                             after the GMWB Effective Date. No additional
                             anniversary values will be calculated thereafter
                             for purposes of the GMWB MAV Base.

                (3) ON AND AFTER THE FIRST WITHDRAWAL AFTER THE GMWB EFFECTIVE
                    DATE:


                    (a)    When the cumulative withdrawals during the Contract
                           Year, including the most recent withdrawal, are not
                           in excess of the GLA, the GMWB BASE will equal the
                           GMWB Base immediately prior to such withdrawal.

                    (b)    When an Excess Withdrawal applies during the
                           Contract Year, the GMWB BASE will equal the lesser
                           of:
                           (i)  the GMWB Base immediately prior to such
                                withdrawal less the Adjusted Excess Withdrawal;
                                or
                           (ii) the Account Value after the withdrawal.


                                      -5-
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                          CONTRACT SCHEDULE (CONTINUED)
                                            Contract Number:     [%999999999]

GMWB RIDER SCHEDULE (CONTINUED)

                EXCESS WITHDRAWAL:

                    (1)    If cumulative withdrawals in a Contract Year have
                           already exceeded the GLA in effect at the time of a
                           withdrawal request, then the entire amount of that
                           withdrawal is an Excess Withdrawal.

                    (2)    If a withdrawal causes the total amount withdrawn
                           during a Contract Year to exceed the GLA in effect
                           at the time of the withdrawal request, then the
                           amount that the cumulative withdrawals are in
                           excess of the GLA is an Excess Withdrawal.

                ADJUSTED EXCESS WITHDRAWAL: An Adjusted Excess Withdrawal is
                equal to the Excess Withdrawal multiplied by an adjustment
                factor. The adjustment factor is calculated by dividing the GMWB
                Base by the Account Value, where both values are determined just
                prior to such withdrawal.

                REQUIRED MINIMUM DISTRIBUTION (RMD): If you are required to make
                withdrawals from Your Contract to satisfy the RMD rules under
                Section 401(a)(9) of the Internal Revenue Code You must notify
                us in writing.

                If We receive such written notification and if We determine that
                the RMD for Your Contract is greater than Your GLA, then any
                reduction to the GMWB Base may be limited as follows:


                    (1)    Notwithstanding section (3)(b) above, if cumulative
                           withdrawals for that Contract Year, including the
                           requested withdrawal, do not exceed the RMD, then
                           We will limit any adjustment factor to not exceed
                           1.0, and the GMWB Base will equal (3)(b)(i) above.

                    (2)    If a withdrawal causes cumulative withdrawals for
                           that Contract Year to exceed the RMD, then We will
                           limit the adjustment factor for a portion of the
                           Excess Withdrawal (equal to the Excess Withdrawal
                           less the amount by which cumulative withdrawals
                           exceed the RMD) to not exceed 1.0. The adjustment
                           factor for the remaining portion of the Excess
                           Withdrawal will be determined as described in the
                           ADJUSTED EXCESS WITHDRAWAL section of the GMWB
                           Rider Schedule.

                AUTOMATIC STEP-UP: On each [3rd] Contract Anniversary after the
                first withdrawal, if the Contract Value is greater than the GMWB
                Base, the GMWB Base will be increased to equal the Contract
                Value.


GMWB SETTLEMENT:
                On any date the Account Value is reduced to zero, the following
                will occur:

                    (1)    any remaining GLA not yet withdrawn in the current
                           Contract Year will be paid in a lump sum in
                           accordance with applicable legal requirements; and
                    (2)    an Annuity Date no earlier than the next Contract
                           Anniversary will be established and monthly annuity
                           payments equal to the GLA divided by 12, payable
                           until the death of the [second] Annuitant, will
                           start on that date; and


                                      -6-
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                          CONTRACT SCHEDULE (CONTINUED)
                                            Contract Number:     [%999999999]

GMWB RIDER SCHEDULE (CONTINUED)

                    (3)    all riders attached to the Base Contract will
                           terminate.


                Different payment intervals or other lifetime annuity payments
                acceptable to Us may be used, but will result in an actuarially
                reduced annuity payment.

CHANGE OF OWNER:

                If there is a change of Owner or an assignment (in states where
                applicable) of this Contract, this Rider will terminate unless
                the Owner is changed under any of the circumstances described
                below:

                    (1)    a spouse of the current Owner is added as an Owner
                           and was neither younger than the minimum age for
                           GMWB Rider nor older than the Maximum Age for GMWB
                           Rider on the GMWB Effective Date; or

                    (2)    a spouse of the current Owner is removed as an
                           Owner; or

                    (3)    as the result of the creation or termination of a
                           trust, the life (or lives) upon which GLA payments
                           under this Rider are based has not changed; or

                    (4)    an Eligible Spousal Beneficiary becomes the Owner
                           while this Rider is still available and on the
                           GMWB Effective Date was not younger than the
                           Minimum Age for GMWB Rider.


SPOUSAL CONTINUATION:
                If the Spousal Continuation Option is elected or is
                automatically applied and this Rider is still available, [the
                GMWB Base will be reset to equal the greater of the Contract
                Value and the GMWB Base, and] the Lifetime Income Percentage
                will be based on the age of the spouse on the Spousal
                Continuation Date subject to the terms and conditions in effect
                at that time.

WAIVER OF SURRENDER CHARGE:
                Any Surrender Charge that would otherwise apply to the portion
                of a withdrawal that is not an Excess Withdrawal will be waived.

PREMIUM LIMITATION:
                No additional Premiums can be paid on or after the date You make
                Your first withdrawal on or after the GMWB Effective Date.

BENEFIT AVAILABLE ON MATURITY DATE:

                The Benefit Available on Maturity Date will provide monthly
                annuity payments equal to the GLA divided by 12 until the death
                of the [second] Annuitant.


                We must receive written notification of Your election of such
                Benefit Available on Maturity Date no earlier than 90 days but
                at least 3 days prior to the Maturity Date.

                Different payment intervals or other lifetime annuity payments
                acceptable to Us may be used, but will result in an actuarially
                reduced annuity payment.


                                      -7-
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                          CONTRACT SCHEDULE (CONTINUED)
                                            Contract Number:     [%999999999]

GMWB RIDER SCHEDULE (CONTINUED)


GMWB CHARGE:
                                           Current              Maximum
                                           -------              -------

                GMWB Charge Percentage:    [0.75% annually]     1.50% annually

                The   GMWB Charge is calculated on each Monthaversary as
                      follows:

                    (1)  the GMWB Base is determined on the Monthaversary;

                    (2)  that amount is multiplied by the current GMWB
                         Charge Percentage;

                    (3)  the resulting amount is divided by 12.


                The sum of the GMWB Charges calculated on each of the three
                preceding Monthaversaries is deducted from the Contract Value on
                each Quarterversary.

                If the Contract Date falls on the 29th, 30th or 31st, We will
                use the last day of the month for any month that does not have a
                corresponding Monthaversary or Quarterversary for purposes of
                calculating and deducting GMWB Charges.

                If the GMWB Rider is terminated other than on a Quarterversary,
                We will deduct from the Contract Value the pro-rata portion of
                any GMWB Charges calculated on any prior Monthaversary but not
                yet collected.


                The GMWB Charge is deducted from each subaccount in the ratio of
                Your interest in each subaccount to Your Account Value on the
                date the charge is collected.


                The Contract Value and Surrender Value are reduced by any GMWB
                Charges calculated but not yet collected.


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