I-1 - Preliminary Official Statement Series 2021A Refunding

Original Issue Premium The Bonds maturing in the years _____________ are being issued at a premium to the principal amount payable at maturity. Except in the case of dealers, which are subject to special rules, Bondholders who acquire the Bonds at a premium must, from time to time, reduce their federal tax bases for the Bonds for purposes of determining gain or loss on the sale or payment of such Bonds. Premium generally is amortized for federal income tax purposes on the basis of a bondholder’s constant yield to maturity or to certain call dates with semiannual compounding. Bondholders who acquire any Bonds at a premium might recognize taxable gain upon sale of the Bonds, even if such Bonds are sold for an amount equal to or less than their original cost. Amortized premium is not deductible for federal income tax purposes. Bondholders who acquire any Bonds at a premium should consult their tax advisors concerning the calculation of bond premium and the timing and rate of premium amortization, as well as the state and local tax consequences of owning and selling the Bonds acquired at a premium. Original Issue Discount The Bonds maturing in the years ________________ (collectively, the “Discount Bonds”) are being sold at a discount from the principal amount payable on such Discount Bonds at maturity. The difference between the price at which a substantial amount of the Discount Bonds of a given maturity is first sold to the public (the “Issue Price”) and the principal amount payable at maturity constitutes “original issue discount” under the Internal Revenue Code. The amount of original issue discount that accrues to a holder of a Discount Bond under section 1288 of the Internal Revenue Code is excluded from federal gross income to the same extent that stated interest on such Discount Bond would be so excluded. The amount of the original issue discount that accrues with respect to a Discount Bond under section 1288 is added to the owner’s federal tax basis in determining gain or loss upon disposition of such Discount Bond (whether by sale, exchange, redemption or payment at maturity). Interest in the form of original issue discount accrues under section 1288 pursuant to a constant yield method that reflects semiannual compounding on dates that are determined by reference to the maturity date of the Discount Bond. The amount of original issue discount that accrues for any particular semiannual accrual period generally is equal to the excess of (1) the product of (a) one-half of the yield on such Discount Bonds (adjusted as necessary for an initial short period) and (b) the adjusted issue price of such Discount Bonds, over (2) the amount of stated interest actually payable. For purposes of the preceding sentence, the adjusted issue price is determined by adding to the Issue Price for such Discount Bonds the original issue discount that is treated as having accrued during all prior semiannual accrual periods. If a Discount Bond is sold or otherwise disposed of between semiannual compounding dates, then the original issue discount that would have accrued for that semiannual accrual period for federal income tax purposes is allocated ratably to the days in such accrual period. An owner of a Discount Bond who disposes of such Discount Bond prior to maturity should consult owner’s tax advisor as to the amount of original issue discount accrued over the period held and the amount of taxable gain or loss upon the sale or other disposition of such Discount Bond prior to maturity. Owners who purchase Discount Bond in the initial public offering but at a price different than the Issue Price should consult their own tax advisors with respect to the tax consequences of the ownership Discount Bond. The Internal Revenue Code contains provisions relating to the accrual of original issue discount in the case of subsequent purchasers of bonds such as the Discount Bonds. Owners who do not purchase Discount Bonds in the initial offering should consult their own tax advisors with respect to the tax consequences of the ownership of the Discount Bonds. Original issue discount that accrues in each year to an owner of a Discount Bond may result in collateral federal income tax consequences to certain taxpayers. No opinion is expressed as to state and local income tax treatment of original issue discount. All owners of Discount Bonds should consult their own tax advisors with respect to the federal, state, local and foreign tax consequences associated with the purchase, ownership, redemption, sale or other disposition of Discount Bonds. LEGAL MATTERS Legal matters incident to the authorization, issuance and sale of the Bonds and with regard to the tax-exempt status of the interest thereon (see “TAX EXEMPTION AND RELATED TAX MATTERS” herein) are subject to the approving legal opinion of Dorsey & Whitney LLP, Des Moines, Iowa, Bond Counsel, a form of which is attached hereto as “APPENDIX B – FORM OF BOND COUNSEL OPINION.” Signed copies of the opinion, dated and premised on law in effect as of the date of original delivery of the Bonds, will be delivered to the Underwriter at the time of such original delivery. The Bonds are offered subject to prior sale and to the approval of legality of the Bonds by Bond Counsel. Dorsey & Whitney LLP is also serving as Disclosure Counsel to the Issuer in connection with issuance of the Bonds. The legal opinion to be delivered will express the professional judgment of Bond Counsel, and by rendering a legal opinion, Bond Counsel does not become an insurer or guarantor of the result indicated by that expression of professional judgment or of the transaction or the future performance of the parties to the transaction. -10-