SEPARATE ACCOUNT INVESTMENT RIDER FOR INVESTMENT IN CERTAIN FUNDS

This rider is added to the Group Annuity Contract issued by us of which it is a
part. All terms defined in the contract have the same meaning where used in this
rider. The effective date of this rider is the latest of (i) the Contract Date,
(ii) the date this rider has been approved for use in the state of issue, or
(iii) the date stated in the amendment adding this rider to the contract.

The purpose of this rider is to allow the contract to participate in our
Separate Accounts which invest in nonproprietary Mutual Funds and other
authorized investments. We reserve the right to limit both the number of
Separate Accounts available under the contract and the number available to each
Member.

Although all Separate Accounts listed in Schedule 1 may be available under this
contract, you may send us Notification indicating you want the contract
administered so that money held under this contract will not participate in one
or more of these Separate Accounts. You may revoke your Notification by sending
us a new Notification.

    1. DEFINITIONS.  

Management Charge means the charge consisting of the investment management
charge and the contract expense charge applicable to this class of contracts for
each Separate Account, less any expense credits. The Management Charge will be
shown in the Table of Separate Account Features of this rider.

Mutual Fund means any diversified, open-end management investment company
registered under The Investment Company Act of 1940 which is the underlying
investment of the Separate Account which is made available by Principal Life
Insurance Company, as listed in Schedule 1.

Within this rider, Mutual Fund shall also mean a portfolio established within a
particular Mutual Fund as described in the prospectus for that Mutual Fund, as
such prospectus may be amended or supplemented from time to time.

We reserve the right, subject to compliance with applicable law, to make
additions to, deletions from, substitution for, or combinations of, the Mutual
Funds listed in Schedule 1.

Net Asset Value (NAV) means the price per share represented as a dollar amount.

Separate Account(s) means each Separate Account established under this rider,
which is maintained by us, made available to you by us, and identified in
Schedule 1 of this rider. Each Separate Account is a pooled Separate Account for
use by our retirement plan customers. The amounts held in each Separate Account
will be invested and reinvested in accordance with applicable law. Amounts
credited to any Separate Account identified in Schedule 1 of this rider shall be
invested in the shares of the corresponding Mutual Fund.

We reserve the right, subject to compliance with applicable law, to make
additions to, deletions from, substitution for, or combinations of, the Separate
Accounts listed in Schedule 1.

Valuation Date means the date we determine the value of a Separate Account,
Valuation Dates will occur on dates we determine, but at least on the last
Business Day of a calendar month. Valuation will occur at the end of each such
day, according to our then-current procedures.

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Valuation Period means the period from the end of a Valuation Date to the end of
the next Valuation Date.

  2.

DETERMINING SEPARATE ACCOUNT VALUES. The value of a Separate Account is its
market value of the shares invested n the Mutual Fund multiplied by the Mutual
Fund's NAV for that Valuation Date. The value of all Separate Accounts will
always be expressed in U.S. dollars. We will determine the value of a Separate
Account on each Valuation Date.

  3.

MANAGEMENT CHARGES. The Management Charge under each Separate Account will be a
percentage of the value of the amounts in such Separate Account, subject to the
equivalent of the maximum annual percentage listed in the Table of Separate
Account Features of this rider. We reserve the right to charge the Management
Charge to any charge up to the maximum limit at any time by giving you written
notice at least 30 days before the date the change is to take effect. The Mutual
Fund’s management charges are separate from the Management Charges of the
Separate Accounts and can be found in the prospectus for the corresponding
Mutual Fund.

The Management Charge will be deducted pro-rata from each Separate Account on
each Valuation Date for the number of calendar days within the Valuation Period
ending on such Valuation Date.

  4.

SEPARATE ACCOUNT INVESTMENT. A Separate Account investment is established for
each Member for each Separate Account to which the member directs Contributions.

  5.

RETURNS CREDITED TO SEPARATE ACCOUNT INVESTMENTS. Each Separate Account
Investment established under this contract will be credited with its portion of
the return associated with the appropriate Separate Account. The return for a
Separate Account will be based on the change in value of that Separate Account
less any Management Charge.

In order to track the returns for the Separate Account Investments established
under this contract, we will use a unit value system of recordkeeping, unless we
determine that another recordkeeping system would b more appropriate.

  6.

UNIT VALUE SYSTEM OF RECORDKEEPING. Under a unit value system of recordkeeping,
we will calculate a unit value for each Separate Account on each Valuation Date.
To calculate the unit value, we first determine the market value of the Separate
Account as described in Section 2 of this rider. Then, we will calculate the
Management Charge as described in Section 3 of this rider. Finally, we will
calculate the unit value by dividing the market value of the Separate Account
less any Management Charge by the units held in the Separate Account.

We will calculate the unit value applicable to each Separate Account Investment
on each Valuation Date. The unit value will be based upon the total value of the
Separate Account and the number of existing Separate Account units.

Contributions or transfers to a Separate Account Investment increase the numbeb
of Separate Account units credited to it. Transfers and payments from a Separate
Account Investment reduce the number of Separate Account units. The increase or
decrease in the number of Separate Account units is calculated by dividing the
dollar amount of the contribution, transfer or payment by the applicable unit
value.

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When crediting Contributions and transfers to a Separate Account Investment we
will use the unit value applicable to the Separate Account Investment for the
Valuation Date on which we accept the Contribution or transfer.

A Contribution is considered accepted on the date we receive both the money and
all the information necessary and in good form to allocate and credit the
Contribution.

  7.

DEPOSITS TO SEPARATE ACCOUNTS; RESTRICTIONS AND ORDER OF ENTRY. We reserve the
right to temporarily or permanently close a Separate Account; thereby we defer
or stop your ability to direct Contributions and transfers to a Separate
Account. We reserve the right to require you to transfer existing account
balances out of a Separate Account which has been temporarily or permanently
closed.

We may exercise these rights due to a particular underlying Mutual Fund’s
provisions. However, our rights are not limited to such circumstances.

We will notify you in writing of our intent to temporarily or permanently close
a Separate Account. Contributions or transfers directed to a Separate Account
that we have closed on a temporary or permanent basis will be directed to
another Separate Account of your choice.

If we require the existing account balances be transferred out of the
temporarily or permanently closed Separate Account, you will have 60 days to
request transfer as described in 8. below. If after 60 days we have not received
Notification of where to transfer such Separate Account balance, we will
transfer the balance to the Separate Accounts available under this rider, in
equal dollar amounts, or, if no other Separate Accounts are available, we will
direct the balance to the Guaranteed Interest Investment with the shortest
Guarantee Period.

  8.

TRANSFERS AND PAYMENTS FROM A SEPARATE ACCOUNT INVESTMENT. We will, upon
Notification from you (the Member if permitted by the Plan), and subject to our
right to defer a transfer or payment as described in Section 10 of this rider.

    a)

Transfer to the Member’s Guaranteed Interest Investment or any Separate Account
Investment available under the contract all or any portion of the Separate
Account Investment specified, or

    b)

Transfer to another Funding Agent all or any portion of the Member's Separate
Account Investment specified, or

    c)

Pay the Member an amount equal to all or any portion of the Member's Separate
Account Investment specified.

   

The amount to be paid or transferred will be determined and paid or transferred
within seven Business Days after (i) the Valuation Date on which we receive the
Notification or (ii) a later Valuation Date specified in the Notification.
Payments and transfers will be made in accordance with our then-current
procedures. We will notify you in writing of these procedures. The amount
transferred or paid will be deducted from the Separate Account Investment from
which such transfer or payment was requested on the date of such transfer or
payment. Each transfer to another Separate Account Investment may occur only on
a Valuation Date of that Separate Account.

We are not responsible for the application of amounts transferred to another
Funding Agent.

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      9.

MUTUAL FUND LIMITATION. Without regard to any other feature of the contract or
this rider, if any limitation or delay is imposed by the underlying Mutual Fund
we will be unable to transfer, make payments, or apply amounts held under these
Separate Accounts.

  10.

LIMITATIONS ON TRANSFERS AND PAYMENTS FROM A SEPARATE ACCOUNT INVESTMENT. In
general, transfers and payments from a Separate Account Investment will be made
within seven Business Days after the first Valuation Date following the request
specified in Section 8 of this rider. We reserve the right, however, to defer
such transfers or payments up to the maximum number of days shown in the Table
of Separate Account Features of this rider for each Separate Account. If we
defer any transfer or payment under this Section, we will determine the amount
to be transferred or paid on the date transfer or payment occurs. We will notify
you in the event of any deferment of more than 30 days under the provisions of
this Section.

These limitations will not apply to the payments to the beneficiary of a Member
due to the Member’s death, payments to a Member due to disability or retirement
under the Plan and to purchases of annuity under Article IV, Section 2 of the
contract.

Special Limitation for Separate Accounts. We reserve the right to make the
portion of a requested transfer in excess of $20,000,000 in substantially equal
monthly installments over a period not to exceed 36 months, if, in the 36 month
period which ends on the requested date of transfer, all transfers and payments
form the total of all Separate Account Investments invested in a particular
Separate Account totals $20,000,000 or more. For purposes of this limitation,
transfers and payments from any other Separate Account Investments included in
the Separate Account from any other contracts or policies issued in connection
with the Plan or with any other retirement plan of the Employer will be included
as a transfer or payment from a Separate Account Investment. If this limitation
is imposed by us, the first installment will be made one month after the date of
request, or on such later date that you specify.

  11.

PLANS WHICH MAY INVEST IN THE SEPARATE ACCOUNTS. The Separate Accounts are not
registered with the Federal Securities and Exchange Commission and therefore
only Plans which meet certain requirements under the Code may invest in the
Separate Accounts. If the Internal Revenue Service or a court makes a final
determination that the Plan no longer meets the requirements of a Qualified
Plan, we will require that you transfer any amounts held in any Separate
Accounts. If we decide that you must transfer amounts out of the Separate
Accounts, we will send you a notice describing your options. Your Notification
must clearly specify the Guaranteed Interest Investment(s) or the Funding Agent
to which you want the amounts transferred. If we do not receive an acceptable
Notification from you within five Business Days, we will transfer these amounts
to the Guaranteed Interest Investment with the shortest duration.

  12.

FUNDS. We are the sole owner of all amounts held in the Separate Accounts. We
may exercise all owner's rights in regard to all amounts in any Separate Account
Investment or Separate Account, including, but not limited to the following:

    a) The right to hold, sell, exchange, convey or transfer.     b)

The right to exercise any conversion privileges, subscription rights, or other
options, and to make any payments incidental thereto.

    c)

The right to oppose, or to consent to, or otherwise participate in, corporate
reorganizations or other changes affecting corporate securities.

    d) The right to foreclose any loan on real estate.

PRINCIPAL LIFE INSURANCE COMPANY

PRESIDENT AND
CHIEF EXECUTIVE OFFICER

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TABLE OF SEPARATE ACCOUNT FEATURES

                                              Current       Maximum   Maximum No.
                                               Annual        Annual      Days
                                            Mgt. Charge   Mgt. Charge  Allowed to
Separate Account                             Percentage   Percentage     Defer
                                                                       Transfers
                                                                     or Payments

Putnam Voyager (M)                              0.00         3.00      270
Separate Account

Putnam Investors (M)                            0.00         3.00      270
Separate Account

Putnam Equity                                   0.00         3.00      270
Income (M)
Separate Account

Putnam High                                     0.00         3.00      270
Yield Trust II (M)
Separate Account

American Century                                0.00         3.00      270
Ultra (Adv)
Separate Account

American Century                                0.00         3.00      270
Select (Adv)
Separate Account

American Century                                0.00         3.00      270
Value (Adv)
Separate Account

American Century                                0.00         3.00      270
Income & Growth (Adv)
Separate Account

American Century                                0.00         3.00      270
Small Cap Value (Adv)
Separate Account

Fidelity Advisor                                0.00         3.00      270
Equity Growth (T)
Separate Account

Fidelity Advisor Growth                         0.00         3.00      270
Opportunities (T)
Separate Account

Fidelity Advisor                                0.00         3.00      270
Mid-Cap (T)
Separate Account

Fidelity Advisor                                0.00         3.00      270
Overseas (T)
Separate Account

Fidelity Advisor                                0.00         3.00      270
Value Strategies (T)
Separate Account

Fidelity Advisor                                0.00         3.00      270
Small Cap (T)
Separate Account

Mason Street                                    0.15         3.00      270
Aggressive Growth
Stock (A)
Separate Account**

Mason Street                                    0.15         3.00      270
International Equity (A)
Separate Account**

Mason Street                                    0.15         3.00      270
Asset Allocation (A)
Separate Account

Mason Street                                    0.15         3.00      270
High Yield Bond (A)
Separate Account

Janus Adviser                                   0.15         3.00      270
Aggressive
Growth (Ret)
Separate Account

Janus Adviser Capital                           0.15         3.00      270
Appreciation (Ret)
Separate Account

INVESCO Small                                   0.00         3.00      270

Company Growth
Separate Account

INVESCO Leisure                                 0.00         3.00      270

Separate Account

INVESCO                                         0.00         3.00      270
Equity Income
Separate Account

* This charge is the charge made by us only, and it dos not include any
management charge of the Mutual Fund. Please see the appropriate prospectuses
for such charges.

** These Separate Accounts are only available to cases sold by a Northwestern
Mutual Life agent.

SCHEDULE 1

       SEPARATE ACCOUNT                              MUTUAL FUND

Putnam Voyager (M) Separate Account         Putnam Voyager (M Shares)

Putnam Investors (MP Separate Account       Putnam Investor (M Shares)

Putnam Equity Income (M) Separate Account   Putnam Equity Income (M Shares)

Putnam High Yield Trust II (M)              Putnam High Yield Trust II (M Shares)
Separate Account

American Century Ultra (Adv)                American Century Ultra
Separate Account                            (Advisor Shares)

American Century Select (Adv)               American Century Select
Separate Account                            (Advisor Shares)

American Century Value (Adv)                American Century Value
Separate Account                            (Advisor Shares)

American Century Income & Growth (Adv)      American Century Income and Growth
Separate Account                            (Advisor Shares)

American Century Small Cap Value (Adv)      American Century Small Cap Value
Separate Account                            (Advisor Shares)

Fidelity Advisor Equity Growth (T)          Fidelity Advisor Equity Growth
Separate Account                            (T Shares)

Fidelity Advisor Growth Opportunities (T)   Fidelity Advisor Growth Opportunity
Separate Account                            (T Shares)

Fidelity Advisor Mid-Cap (T)                Fidelity Advisor Mid Cap
Separate Account                            (T Shares)

Fidelity Advisor Overseas (T)               Fidelity Advisor Overseas
Separate Account                            (T Shares)

Fidelity Advisor Value Strategies (T)       Fidelity Advisor Value Strategies
Separate Account                            (T Shares)

Fidelity Advisor Small Cap (TP              Fidelity Advisor Small Cap
Separate Account                            (Small Shares)

Mason Street Aggressive Growth Stock (A)    Mason Street Aggressive Growth Stock
Separate Account                            (A Shares)

Mason Street International Equity (A)       Mason Street International Equity
Separate Account                            (A Shares)

Mason Street Asset Allocation (A)           Mason Street Asset Allocation
Separate Account                            (A Shares)

Mason Street High Yield Bond (A)            Mason Street High Yield Bond
Separate Account                            (A Shares)

Janus Adviser Aggressive Growth (Ret)       Janus Adviser Aggressive Growth
Separate Account                            (Retirement Shares)

Janus Adviser Capital Appreciation (Ret)    Janus Adviser Capital Appreciation
Separate Account                            (Retirement Shares)

INVESCO Small Company Growth                INVESCO Small Company Growth
Separate Account

INVESCO Leisure                             INVESCO Leisure

Separate Account

INVESCO Equity Income                       INVESCO Equity Income
Separate Account