Alexandria Real Estate Equities, Inc. $1,000,000,000 7.250% SeriesA Fixed-to-Fixed Reset RateJunior Subordinated Notes due 2057Fully and Unconditionally Guaranteed by Alexandria Real Estate Equities,L.P. We are offering $1,000,000,000 of 7.250% SeriesA Fixed-to-Fixed Reset Rate Junior SubordinatedNotes due2057 (the “notes”). The notes will bear interest (i)from and including the original issuance date to, but excludingFebruary15, 2032 (the “First Reset Date”), at a rate of 7.250% per year and (ii)from and including the FirstReset Date, during each Reset Period (as defined herein), at a rate per year equal to the Five-year U.S.Treasury Rate (as defined herein) as of the most recent Reset Interest Determination Date (as definedherein) plus a spread of 2.889%, to be reset on each Reset Date (as defined herein); provided, that theinterest rate during any Reset Period will not reset below 7.250% (which equals the initial interest rate onthe notes). Subject to our right to defer interest payments as described below, we will pay interest on the notessemi-annually in arrears on February15 and August15 of each year, beginning on February15, 2027. Thenotes will mature on February15, 2057. The notes will be fully and unconditionally guaranteed on asubordinated unsecured basis by our subsidiary, Alexandria Real Estate Equities, L.P., a Delaware limitedpartnership (the “Operating Partnership”) (the “Guarantee”). We may redeem some or all of the notes at ouroption at the times and at the redemption prices described under the caption “Description of Notes andGuarantee— Redemption.” We will issue the notes only in registered form in minimum denominations of$2,000 and integral multiples of $1,000 in excess thereof. So long as no event of default with respect to the notes has occurred and is continuing, we may, at ouroption, on one or more occasions, defer payment of all or part of the current and accrued interest otherwisedue on the notes for a period of up to five consecutiveyears (each such period, commencing on the date thatthe first such interest payment would otherwise have been made, an “Optional Deferral Period”), asdescribed in this prospectus supplement. Deferred interest payments with respect to the notes will accrueadditional interest at a rate equal to the interest rate then applicable to the notes, compounded on eachinterest payment date, to the extent permitted by law. During any such Optional Deferral Period, we and theOperating Partnership may not, among other things, declare or pay any dividends or distributions, other thana Permitted REIT Status Dividend (as defined herein) and any related distributions by the OperatingPartnership on its equity interests in an amount not to exceed the amount necessary for us to pay a declaredPermitted REIT Status Dividend, as further described under the caption “Description of Notes andGuarantee — Certain Limitations During an Optional Deferral Period.” The notes will be our junior subordinated unsecured obligations and will rank subordinate and junior inright of payment to all of our existing and future Senior Debt, as described under “Description of Notes andGuarantee — Ranking; Subordination.” The notes will also rank effectively junior to our secured debt, to theextent of the value of the collateral securing such secured debt, and to all debt and other liabilities of oursubsidiaries from time to time outstanding, other than the obligations of the Operating Partnership under theGuarantee. The Guarantee will be a subordinated unsecured obligation of the Operating Partnership and willrank subordinate and junior in right of payment to all existing and future Senior Debt of the OperatingPartnership. The Guarantee will also rank effectively junior to any secured debt of the OperatingPartnership, to the extent of the value of the collateral securing such secured debt, and to all debt and otherliabilities of the Operating Partnership’s subsidiaries. The notes and the Guarantee will rank senior to allequity securities of us and the Operating Partnership, respectively. As described under “Use of Proceeds,” we intend to use the net proceeds of the offering of the notes forgeneral corporate purposes, which may include working capital, the reduction of the outstanding balance, ifany, on our unsecured senior line of credit, the reduction of the outstanding indebtedness, if any, under ourcommercial paper program, the repayment of other debt and the selective development, redevelopment oracquisition of properties. Pending such use, we may invest the net proceeds in high-quality short-termsecurities and/or use such proceeds temporarily for general working capital and other general corporatepurposes. The notes offered hereby are a new issue of securities. No market currently exists for the notes. We donot intend to list the notes on any national securities exchange. Investing in our notes involves risks. See “Risk Factors” beginning on pageS-8. (1)Plus accrued interest, if any