PRINCIPAL LIFE INCOME FUNDINGS TRUST 2008-77 PRINCIPAL® LIFE CORENOTES®

THIS NOTE IS A GLOBAL NOTE WITHIN THE MEANING OF THE INDENTURE (HEREINAFTER DEFINED) AND IS REGISTERED IN THE NAME OF A DEPOSITARY (AS DEFINED IN THE INDENTURE) OR A NOMINEE OF A DEPOSITARY. THIS NOTE IS NOT EXCHANGEABLE FOR NOTES REGISTERED IN THE NAME OF A PERSON OTHER THAN THE DEPOSITARY OR ITS NOMINEE EXCEPT IN THE LIMITED CIRCUMSTANCES DESCRIBED IN THE INDENTURE, AND NO TRANSFER OF THIS NOTE (OTHER THAN A TRANSFER OF THIS NOTE AS A WHOLE BY THE DEPOSITARY TO A NOMINEE OF THE DEPOSITARY OR BY A NOMINEE OF THE DEPOSITARY TO THE DEPOSITARY OR ANOTHER NOMINEE OF THE DEPOSITARY) MAY BE REGISTERED EXCEPT IN THE LIMITED CIRCUMSTANCES DESCRIBED IN THE INDENTURE.

UNLESS THIS NOTE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION (“DTC”), TO THE TRUST (HEREINAFTER DEFINED) OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND UNLESS ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO CEDE & CO. OR SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

PRINCIPAL LIFE INCOME FUNDINGS TRUST 2008-77

PRINCIPAL ^® LIFE CORENOTES ^®

Original Issue Date: September 4, 2008

Issue Price: 100%

Stated Maturity Date: September 17, 2018

Settlement Date: September 4, 2008

Securities Exchange Listing: o Yes þ No. If yes, indicate name(s) of Securities Exchange(s):                                          .

Depositary: The Depository Trust Company

Authorized Denominations: $1,000

Collateral held in the Trust: Principal Life Insurance Company Funding Agreement No. 4-55666, the related Principal Financial Group, Inc. Guarantee which fully and unconditionally guarantees the payment obligations of Principal Life Insurance Company under the Funding Agreement, all proceeds of the Funding Agreement and the related Guarantee and all rights and books and records pertaining to the foregoing.

Interest Rate or Formula:

Fixed Rate Note: þ Yes o No. If yes,

Discount Note: o Yes þ No. If yes,

     Total Amount of Discount:
     Initial Accrual Period of Discount:
     Interest Payment Dates:
     Additional/Other Terms:

Redemption Provisions: þ Yes o No. If yes,
     Initial Redemption Date: September 15, 2009
     Additional/Other Terms: In whole only and not in part; any redemption date will be an Interest Payment Date falling on or after the Initial
     Redemption Date.

Repayment Provisions: o Yes þ No. If yes,
     Repayment Date(s):
     Repayment Price:
     Additional/Other Terms:

Floating Rate Note: o Yes þ No. If yes,
     Regular Floating Rate Notes o
     Floating Rate/ Fixed Rate Notes: o
     Interest Rate:
     Interest Rate Basis(es):
     LIBOR o
           o LIBOR Reuters Page:
          LIBOR Currency:
     CMT Rate o
     Designated Reuters Page:
               If FEDCMT
                o Weekly Average
                o Monthly Average
          Designated CMT Maturity Index:
     CD Rate o
     Commercial Paper Rate o
     Constant Maturity Swap Rate o
     Federal Funds Open Rate o
     Federal Funds Rate o
     Prime Rate o
     Treasury Rate o

     Index Maturity:

     Spread and/or Spread Multiplier:

     Initial Interest Rate, if any:

     Initial Interest Reset Date:

     Interest Reset Dates:

     Interest Determination Date(s):

     Interest Payment Dates:

     Maximum Interest Rate, if any:

     Minimum Interest Rate, if any:

     Fixed Rate Commencement Date, if any:

     Floating Rate Commencement Date, if any:

     Fixed Interest Rate, if any:

     Day Count Convention:

     Additional/Other Terms:

Regular Record Date(s): 15 calendar days prior to the Interest Payment Date

Sinking Fund: Not Applicable

Calculation Agent: Citibank, N.A.

Additional/Other Terms:

Survivor’s Option: þ Yes o No.
     If yes, the attached Survivor’s Option Rider is incorporated into this Note.

Trust Put Limitation: 2.00%

     The Principal Life Income Fundings Trust designated above (the “Trust”), for value received, hereby promises to pay to Cede & Co., or its registered assigns, the Principal Amount specified above on the Stated Maturity Date specified above and, if so specified above, to pay interest thereon from the Original Issue Date specified above or from the most recent Interest Payment Date specified above to which interest has been paid or duly provided for at the rate per annum determined in accordance with the provisions on the reverse hereof and as specified above, until the principal hereof is paid or made available for payment. Payments of principal, premium, if any, and interest hereon will be made in the lawful currency of the United States of America (“U.S. Dollars” or “United States dollars”). The “Principal Amount” of this Note at any time means (1) if this Note is a Discount Note (as hereinafter defined), the Amortized Face Amount (as hereinafter defined) at such time (as defined in Section 3(c) on the reverse hereof) and (2) in

all other cases, the Principal Amount hereof. Capitalized terms not otherwise defined herein shall have their meanings set forth in the Indenture, dated as of the date of the Pricing Supplement (the “Indenture”), between Citibank, N.A., as the indenture trustee (the “Indenture Trustee”), and the Trust, or on the face hereof.

     This Note will mature on the Stated Maturity Date, unless its principal (or any installment of its principal) becomes due and payable prior to the Stated Maturity Date, whether, as applicable, by the declaration of acceleration of maturity, notice of redemption by the Trust or otherwise (the Stated Maturity Date or any date prior to the Stated Maturity Date on which this Note becomes due and payable, as the case may be, is referred to as the “Maturity Date”).

     A “Discount Note” is any Note that has an Issue Price that is less than 100% of the Principal Amount thereof by a percentage that is equal to or greater than 0.25% multiplied by the product of the principal amount of the Notes and the number of full years to the Stated Maturity Date.

     Unless otherwise specified above, the interest payable on each Interest Payment Date or the Maturity Date will be the amount of interest accrued from and including the Original Issue Date or from and including the last Interest Payment Date to which interest has been paid or duly provided for, as the case may be, to, but excluding, such Interest Payment Date or the Maturity Date, as the case may be.

     Unless otherwise specified above, the interest payable on any Interest Payment Date will be paid to the Holder on the Regular Record Date for such Interest Payment Date, which Regular Record Date shall be the fifteenth (15th) calendar day, whether or not a Business Day, immediately preceding the related Interest Payment Date; provided that, notwithstanding any provision of the Indenture to the contrary, interest payable on any Maturity Date shall be payable to the Person to whom principal shall be payable; and provided, further, that unless otherwise specified above, in the case of a Note initially issued between a Regular Record Date and the Interest Payment Date relating to such Regular Record Date, interest for the period beginning on the Original Issue Date and ending on such Interest Payment Date shall be paid on the Interest Payment Date following the next succeeding Regular Record Date to the Holder on such next succeeding Regular Record Date.

     Payments of principal of, and premium, if any, and interest and other amounts due and owing, if any, will be made through the Indenture Trustee to the account of DTC or its nominee and will be made in accordance with depositary arrangements with DTC.

     Unless otherwise specified on the face hereof, the Holder hereof will not be obligated to pay any administrative costs imposed by banks in making payments in immediately available funds by the Trust. Unless otherwise specified on the face hereof, any tax assessment or governmental charge imposed upon payments hereunder, including, without limitation, any withholding tax, will be borne by the Holder hereof.

     REFERENCE IS HEREBY MADE TO THE FURTHER PROVISIONS OF THIS NOTE SET FORTH ON THE REVERSE HEREOF. SUCH FURTHER PROVISIONS SHALL FOR ALL PURPOSES HAVE THE SAME EFFECT AS IF SET FORTH AT THIS PLACE.

     Unless the certificate of authentication hereon shall have been executed by the Indenture Trustee pursuant to the Indenture, this Note shall not be entitled to any benefit under such Indenture or be valid or obligatory for any purpose.

     IN WITNESS WHEREOF, the Trust has caused this instrument to be duly executed, by manual or facsimile signature.

CERTIFICATE OF AUTHENTICATION

     This is one of the Notes of the Principal Life Income Fundings Trust specified on the face of this Note referred to in the within-mentioned Indenture.

[REVERSE FORM OF NOTE]

Section 1. General . This Note is one of a duly authorized issue of Notes of the Trust. The Notes are issued pursuant to the Indenture.

Section 2. Currency . This Note is denominated in, and payments of principal, premium, if any, and/or interest, if any, will be made in U.S. Dollars.

Section 3. Determination of Interest Rate and Certain Other Terms .

(i) This Note will bear interest at the rate per annum specified on the face hereof. Interest on this Note will be computed on the basis of a 360-day year of twelve 30-day months.

(ii) Unless otherwise specified on the face hereof, the Interest Payment Dates for this Note will be as follows:

(iii) If any Interest Payment Date or the Maturity Date of this Note falls on a day that is not a Business Day, the Trust will make the required payment of principal, premium, if any, and/or interest or other amounts on the next succeeding Business Day, and no additional interest will accrue in respect of the payment made on that next succeeding Business Day.

(i) Interest Rate Basis . Interest on this Note will be determined by reference to the applicable Interest Rate Basis or Interest Rate Bases, which may, as described below, include the CD Rate, the CMT Rate, the Commercial Paper Rate, the Constant Maturity Swap Rate, the Federal Funds Open Rate, the Federal Funds Rate, LIBOR, the Prime Rate or the Treasury Rate (each as defined below).

(ii) Effective Rate . The rate derived from the applicable Interest Rate Basis or Interest Rate Bases will be determined in accordance with the related provisions below. The interest rate in effect on each day will be based on: (1) if that day is an Interest Reset Date, the rate determined as of the Interest Determination Date immediately preceding that Interest Reset Date; or (2) if that day is not an Interest Reset Date, the rate determined as of the Interest Determination Date immediately preceding the most recent Interest Reset Date.

(iii) Spread; Spread Multiplier; Index Maturity . The “Spread” is the number of basis points (one one-hundredth of a percentage point) specified on the face hereof to be added to or subtracted from the related Interest Rate Basis or Interest Rate Bases applicable to this Note. The “Spread Multiplier” is the percentage specified on the face hereof of the related Interest Rate Basis or Interest Rate Bases applicable to this Note by which the Interest Rate Basis or Interest Rate Bases will be multiplied to determine the applicable interest rate. The “Index Maturity” is the period to maturity of the instrument or obligation with respect to which the related Interest Rate Basis or Interest Rate Bases will be calculated.

(iv) Regular Floating Rate Note . Unless this Note is specified on the face hereof as a Floating Rate/Fixed Rate Note, this Note (a “Regular Floating Rate Note”) will bear interest at the rate determined by reference to the applicable Interest Rate Basis or Interest Rate Bases:(1) plus or minus the applicable Spread, if any; and/or (2) multiplied by the applicable Spread Multiplier, if any. Commencing on the first Interest Reset Date, the rate at which interest on this Regular Floating Rate Note is payable will be reset as of each Interest Reset Date; provided, however , that the interest rate in effect for the period, if any, from the Original Issue Date to the first Interest Reset Date will be the Initial Interest Rate.

(v) Floating Rate/Fixed Rate Notes . If this Note is specified on the face hereof as a “Floating Rate/Fixed Rate Note”, this Note will bear interest at the rate determined by reference to the applicable Interest Rate Basis or Interest Rate Bases: (1) plus or minus the applicable Spread, if any; and/or (2) multiplied by the applicable Spread Multiplier, if any. Commencing on the first Interest Reset Date, the rate at which this Floating Rate/Fixed Rate Note is payable will be reset as of each Interest Reset Date; provided, however , that: (A) the interest rate in effect for the period, if any, from the Original Issue Date to the first Interest Reset Date will be the Initial Interest Rate specified on the face hereof; and (B) the interest rate in effect commencing on the Fixed Rate Commencement Date will be the Fixed Interest Rate, if specified on the face hereof, or, if not so specified, the interest rate in effect on the day immediately preceding the Fixed Rate Commencement Date.

(vi) Interest Reset Dates . The period between Interest Reset Dates will be the “Interest Reset Period.” Unless otherwise specified on the face hereof, the Interest Reset Dates will be, in the case of this Floating Rate Note if by its terms it resets: (1) daily—each business day; (2) weekly—the Wednesday of each week, with the exception of any weekly reset Floating Rate Note as to which the Treasury Rate is an applicable Interest

Rate Basis, which will reset the Tuesday of each week; (3) monthly—the fifteenth day of each calendar month; (4) quarterly—the fifteenth day of March, June, September and December of each year; (5) semi-annually—the fifteenth day of the two months of each year specified on the face hereof; and (6) annually—the fifteenth day of the month of each year specified on the face hereof; provided, however , that, with respect to a Floating Rate/Fixed Rate Note, the rate of interest thereon will not reset after the particular Fixed Rate Commencement Date. If any Interest Reset Date for this Floating Rate Note would otherwise be a day that is not a Business Day, the particular Interest Reset Date will be postponed to the next succeeding Business Day, except that in the case of a Floating Rate Note as to which LIBOR is an applicable Interest Rate Basis and that Business Day falls in the next succeeding calendar month, the particular Interest Reset Date will be the immediately preceding Business Day.

(vii) Interest Determination Dates . The interest rate applicable to a Floating Rate Note for an Interest Reset Period commencing on the related Interest Reset Date will be determined by reference to the applicable Interest Rate Basis as of the particular “Interest Determination Date”, which will be: (1) with respect to the Federal Funds Open Rate—the related Interest Reset Date; (2) with respect to the Federal Funds Rate and the Prime Rate—the Business Day immediately preceding the related Interest Reset Date; (3) with respect to the CD Rate, the Commercial Paper Rate and the CMT Rate—the second Business Day preceding the related Interest Reset Date; (4) with respect to the Constant Maturity Swap Rate—the second U.S. Government Securities business day preceding the related Interest Reset Date, provided, however, that if after attempting to determine the Constant Maturity Swap Rate, such rate is not determinable for a particular Interest Determination Date, then such Interest Determination Date shall be the first U.S. Government Securities business day preceding the original interest determination date for which the Constant Maturity Swap Rate can be determined; (5) with respect to LIBOR—the second London Banking Day (as defined below) preceding the related Interest Reset Date; and (6) with respect to the Treasury Rate—the day of the week in which the related Interest Reset Date falls on which day Treasury Bills (as defined below) are normally auctioned (i.e., Treasury Bills are normally sold at auction on Monday of each week, unless that day is a legal holiday, in which case the auction is normally held on the following Tuesday, except that the auction may be held on the preceding Friday); provided, however , that if an auction is held on the Friday of the week preceding the related Interest Reset Date, the Interest Determination Date will be the preceding Friday. The Interest Determination Date pertaining to a Floating Rate Note, the interest rate of which is determined with reference to two or more Interest Rate Bases, will be the latest Business Day which is at least two Business Days before the related Interest Reset Date for the applicable Floating Rate Note on which each Interest Reset Basis is determinable. “London Banking Day” means a day on which commercial banks are open for business (including dealings in the LIBOR Currency) in London.

(viii) Calculation Dates . The interest rate applicable to each Interest Reset Period will be determined by the Calculation Agent on or prior to the Calculation Date (as defined below), except with respect to LIBOR, which will be determined on the particular Interest Determination Date. Upon request of the Holder of a Floating Rate Note, the

Calculation Agent will disclose the interest rate then in effect and, if determined, the interest rate that will become effective as a result of a determination made for the next succeeding Interest Reset Date with respect to such Floating Rate Note. The “Calculation Date”, if applicable, pertaining to any Interest Determination Date will be the earlier of: (1) the tenth calendar day after the particular Interest Determination Date or, if such day is not a Business Day, the next succeeding Business Day; or (2) the Business Day immediately preceding the applicable Interest Payment Date or the Maturity Date, as the case may be.

(ix) Maximum or Minimum Interest Rate . If specified on the face hereof, this Note may have either or both of a Maximum Interest Rate or a Minimum Interest Rate. If a Maximum Interest Rate is so designated, the interest rate for a Floating Rate Note cannot ever exceed such Maximum Interest Rate and in the event that the interest rate on any Interest Reset Date would exceed such Maximum Interest Rate (as if no Maximum Interest Rate were in effect) then the interest rate on such Interest Reset Date shall be the Maximum Interest Rate. If a Minimum Interest Rate is so designated, the interest rate for a Floating Rate Note cannot ever be less than such Minimum Interest Rate and in the event that the interest rate on any Interest Reset Date would be less than such Minimum Interest Rate (as if no Minimum Interest Rate were in effect) then the interest rate on such Interest Reset Date shall be the Minimum Interest Rate. Notwithstanding anything to the contrary contained herein, the interest rate on a Floating Rate Note shall not exceed the maximum interest rate permitted by applicable law.

(x) Interest Payments . Unless otherwise specified on the face hereof, the Interest Payment Dates will be, in the case of a Floating Rate Note which resets: (1) daily, weekly or monthly—the fifteenth day of each calendar month or on the fifteenth day of March, June, September and December of each year, as specified on the face hereof; (2) quarterly—the fifteenth day of March, June, September and December of each year; (3) semi-annually—the fifteenth day of the two months of each year specified on the face hereof; and (4) annually—the fifteenth day of the month of each year as specified on the face hereof. In addition, the Maturity Date will also be an Interest Payment Date. If any Interest Payment Date other than the Maturity Date for this Floating Rate Note would otherwise be a day that is not a Business Day, such Interest Payment Date will be postponed to the next succeeding Business Day, except that in the case of a Floating Rate Note as to which LIBOR is an applicable Interest Rate Basis and that Business Day falls in the next succeeding calendar month, the particular Interest Payment Date will be the immediately preceding Business Day. If the Maturity Date of a Floating Rate Note falls on a day that is not a Business Day, the Trust will make the required payment of principal, premium, if any, and interest or other amounts on the next succeeding Business Day, and no additional interest will accrue in respect of the payment made on that next succeeding Business Day.

(xi) Rounding . Unless otherwise specified on the face hereof, all percentages resulting from any calculation on this Floating Rate Note will be rounded to the nearest one hundred-thousandth of a percentage point, with five one-millionths of a percentage point

rounded upwards. All dollar amounts used in or resulting from any calculation on this Floating Rate Note will be rounded to the nearest cent.

(xii) Interest Factor . With respect to this Floating Rate Note, accrued interest is calculated by multiplying the principal amount of such Note by an accrued interest factor. The accrued interest factor is computed by adding the interest factor calculated for each day in the particular Interest Reset Period. The interest factor for each day will be computed by dividing the interest rate applicable to such day by 360, in the case of a Floating Rate Note as to which the CD Rate, the Commercial Paper Rate, the Federal Funds Open Rate, the Federal Funds Rate, LIBOR or the Prime Rate is an applicable Interest Rate Basis, or by the actual number of days in the year, in the case of a Floating Rate Note as to which the CMT Rate or the Treasury Rate is an applicable Interest Rate Basis. In the case of a series of Notes that bear interest at floating rates as to which the Constant Maturity Swap Rate is the Interest Rate Basis, the interest factor for each day will be computed by dividing the number of days in the interest period by 360 (the number of days to be calculated on the base is of a year of 360 days with twelve 30-day months (unless (i) the last day of the interest period is the 31st day of a month but the first day of the interest period is a day other than the 30th or 31st day of a month, in which case the month that includes that last day shall not be considered to be shortened to a 30-day month, or (ii) the last day of the interest period is the last day of the month of February, in which case the month of February shall not be considered to be lengthened to a 30-day month)). The interest factor for a Floating Rate Note as to which the interest rate is calculated with reference to two or more Interest Rate Bases will be calculated in each period in the same manner as if only the applicable Interest Rate Basis specified above applied.

(xiii) Determination of Interest Rate Basis . The Calculation Agent shall determine the rate derived from each Interest Rate Basis in accordance with the following provisions.

(A) CD Rate Notes . If the Interest Rate Basis is the CD Rate, this Note shall be deemed a “CD Rate Note.” Unless otherwise specified on the face hereof, “CD Rate” means: (1) the rate on the particular Interest Determination Date for negotiable United States dollar certificates of deposit having the Index Maturity specified on the face hereof as published in H.15(519) (as defined below) under the caption “CDs (secondary market)”; or (2) if the rate referred to in clause (1) is not so published by 3:00 P.M., New York City time, on the related Calculation Date, the rate on the particular Interest Determination Date for negotiable United States dollar certificates of deposit of the particular Index Maturity as published in H.15 Daily Update (as defined below), or other recognized electronic source used for the purpose of displaying the applicable rate, under the caption “CDs (secondary market)”; or (3) if the rate referred to in clause (2) is not so published by 3:00 P.M., New York City time, on the related Calculation Date, the rate on the particular Interest Determination Date calculated by the Calculation Agent as the arithmetic mean of the secondary market offered rates as of 10:00 A.M., New York City time, on that Interest Determination Date, of three leading non-bank dealers in negotiable United States dollar certificates of deposit in The City of New York (which may include the

purchasing agent or its affiliates) selected by the Calculation Agent for negotiable United States dollar certificates of deposit of major United States money market banks for negotiable United States certificates of deposit with a remaining maturity closest to the particular Index Maturity in an amount that is representative for a single transaction in that market at that time; or (4) if the dealers so selected by the Calculation Agent are not quoting as mentioned in clause (3), the CD Rate in effect on the particular Interest Determination Date. “H.15(519)” means the weekly statistical release designated as H.15(519), or any successor publication, published by the Board of Governors of the Federal Reserve System. “H.15 Daily Update” means the daily update of H.15(519), available through the world-wide-web site of the Board of Governors of the Federal Reserve System at http://www.federalreserve.gov/releases/H15/ update, or any successor site or publication.

(B) CMT Rate Notes . If the Interest Rate Basis is the CMT Rate, this Note shall be deemed a “CMT Rate Note.” Unless otherwise specified on the face hereof, “CMT Rate” means: