Exhibit 99.1

SEMI-ANNUAL SERVICER’S CERTIFICATE

Pursuant to Section 4.01(c)(ii) of the Securitized Utility Tariff Property Servicing Agreement, dated as of December 20, 2024 (the “Servicing Agreement”), between, UNION ELECTRIC COMPANY, D/B/A AMEREN MISSOURI, a Missouri corporation, as Servicer (the “Servicer”), and AMEREN MISSOURI SECURITIZATION FUNDING I, LLC, as Issuer (the “Issuer”), the Servicer does hereby certify, for the October 1, 2026, Payment Date (the “Current Payment Date”), as follows:

Capitalized terms used herein have their respective meanings as set forth in the Indenture. References herein to certain sections and subsections are references to the respective sections of the Servicing Agreement or the Indenture, as the context indicates.

									Collection Periods:			April 2026 - September 2026
									Payment Date:			October 1, 2026
1			Collections Allocable and Aggregate Amounts Available for the Current Payment Date:
			Securitized Utility Tariff Charge Remittance
						a.			Estimated Monthly Securitized Utility Tariff Charges Remitted for April 2026 Collection Period												$	2,532,772.48
						b.			Estimated Monthly Securitized Utility Tariff Charges Remitted for May 2026 Collection Period												$	2,416,127.57
						c.			Estimated Monthly Securitized Utility Tariff Charges Remitted for June 2026 Collection Period												$	2,524,547.20
						d.			Estimated Monthly Securitized Utility Tariff Charges Remitted for July 2026 Collection Period3												$	3,071,923.38
						e.			Estimated Monthly Securitized Utility Tariff Charges Remitted for August 2026 Collection Period												$	3,940,498.96
						f.			Estimated Monthly Securitized Utility Tariff Charges Remitted for September 2026 Collection Period												$	3,393,605.50
			i.			Total Estimated Monthly Securitized Utility Tariff Charge Remittances2															$	17,879,475.09
			ii.			Investment Earnings on Collection Account
						iii.			Investment Earnings on Capital Subaccount												$	42,379.62
						iv.			Investment Earnings on Excess Funds Subaccount												$	106,547.85
						v.			Investment Earnings on General Subaccount												$	161,254.37
			vi.			General Subaccount Balance (sum of i through v above)															$	18,189,656.93
			vii.			Excess Funds Subaccount Balance as of Prior Payment Date															$	5,199,919.83
			viii.			Capital Subaccount Balance as of Prior Payment Date															$	2,380,605.00
			ix.			Collection Account Balance (sum of vi through viii above)															$	25,770,181.76
2			Outstanding Amounts as of Prior Payment Date:
			i.			Tranche A-1 Outstanding Principal Amount															$	447,171,774.00
3			Required Funding/Payments as of Current Payment Date (4.i through 4.x):																		$	22,926,667.36

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			Principal																		Principal Due
			i.			Tranche A-1															$	11,850,107.00
			Interest Tranche									Interest Rate			Days in Interest Period1			Principal Balance			Interest Due
			ii.			Tranche A-1						4.85%			180			$447,171,774.00			$	10,843,915.52
																		Required Level			Funding Required
			iii.			Capital Subaccount												$2,380,605.00			$	0.00
4			Allocation of Remittances as of Current Payment Date Pursuant to 8.02(e) of Indenture
			i.			Indenture Trustee Fees and Expenses; Indemnity Amounts (subject to $200,000 cap per annum)															$	0.00
			ii.			Servicing Fee															$	119,030.25
			iii.			Administration Fee															$	25,000.00
			iv.			Other Ongoing Financing Costs (Excluding Income Taxes)															$	(10,942.31)
			v.			Semi-Annual Interest (including any past-due for prior periods)															$	10,843,915.52
			Interest by Tranche												Aggregate			Per $1000 of Original Principal Amount
									a. Tranche A-1 Interest Payment						$	10,843,915.52		$22.78
			vi.			Principal Due and Payable as a Result of an Event of Default or on Final Maturity Date															$	0.00
			vii.			Semi-Annual Principal															$	11,850,107.00
			Principal by Tranche												Aggregate			Per $1000 of Original Principal Amount
									b. Tranche A-1 Principal Payment						$	11,850,107.00		$24.89
			viii.			Other Ongoing Financing Costs, Income Taxes															$	0.00
			ix.			Amount by which Required Capital Level Exceeds Capital Subaccount															$	0.00
			x.			Return on Ameren Missouri Capital Contribution															$	99,556.90
			xi.			Deposit to Excess Funds Subaccount															$	0.00
			xii.			Released to Issuer Upon Retirement of All Notes															$	0.00
			xiii.			Aggregate Requirements as of Current Payment Date															$	22,926,667.36
5			Subaccount Withdrawals as of Current Payment Date (if applicable, pursuant to Section 8.02(e) of Indenture):
			i.			Excess Funds Subaccount															$	(4,737,010.43)
			ii.			Capital Subaccount															$	0.00
			iii.			Total Withdrawals															$	(4,737,010.43)

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6			Outstanding Amount and Collection Account Balance as of Current Payment Date (after giving effect to payments to be made on such Payment Date):
			i.			Tranche A-1															$	435,321,667.00
			ii.			Excess Funds Subaccount Balance including Investment Earnings															$	462,909.40
			iii.			Capital Subaccount Balance															$	2,380,605.00
			iv.			Aggregate Collection Account Balance															$	2,843,514.40
7			Shortfalls in Interest and Principal Payments as of Current Payment Date
			i.			Semi-Annual Interest
									Tranche A-1												$	0.00
			ii.			Semi-Annual Principal
									Tranche A-1												$	0.00
8			Shortfalls in Required Subaccount Levels as of Current Payment Date
			i.			Capital Subaccount															$	0.00
			1 On 30/360 day basis for initial payment date; otherwise use one-half of annual rate.
			2 Does not include reconciliation amounts calculated for the Reconciliation Period for such Collection Period, which will be settled within 60 days of the Payment Date.
			3 Includes amounts calculated for the Reconciliation Period for the prior Collection Period. Based upon Estimated Securitized Utility Tariff Charges remitted during Collection Period (i.e., Estimated Securitized Utility Tariff Charges remitted within two Servicer Business Days of deemed collection date).

IN WITNESS WHEREOF, the undersigned has duly executed and delivered this Semi-Annual Servicer’s Certificate as of the date first above written.

SERVICER:
UNION ELECTRIC COMPANY D/B/A AMEREN MISSOURI, a Missouri corporation
/s/ Mitchell J. Lansford
Name: Title: Date:			Mitchell J. Lansford Vice President and Treasurer September 21, 2026