2017 Attachment O True-Up Stakeholder Meeting Ameren Transmission Company of Illinois August 6, 2018

Purpose is to review ATXI 2017 Transmission Rate True-Up Calculations Agenda Purpose is to review ATXI 2017 Transmission Rate True-Up Calculations Protocol Timeline Attachment O Template Changes ROE Complaint Cases and Impact on True-up calculations 2017 True Up Calculation Total Revenue Requirement Comparison – Projected vs Actual Attachment O/Schedule 9 True-up Attachment MM/Schedule 26-A True-up 2017 MVP Spend 2017 Significant Projects Placed In Service An additional meeting will held to review the 2019 Projected Transmission Rate calculations. Tentatively set for September 25, 2018.

(Forward-Looking Protocols) Protocol timeline Date Schedule (Forward-Looking Protocols) June 1 Posting of annual true-up for prior year September 1 Deadline for annual true-up meeting Posting of net projected revenue requirement for following year October 15 Deadline for annual projected rate meeting November 1 Deadline for joint meeting on regional cost-shared projects March 15 Transmission Owners submit informational filing to the Commission

ATXI Attachment O tariff Changes Docket ER17-2323 FERC Order on May 31, 2018 Effective January 1, 2018 for ATXI Approved additional lines in the Income Tax Section (Page 3, Lines 24a/24b and 26a/26b) Modification to return to (or recover from) customers excess (or deficient) accumulated deferred income taxes (ADIT) resulting from tax law or rate changes An adjustment to recognize the effects of permanent differences between tax accounting and financial reporting, such as those associated with the equity component of Allowance for Funds Used During Construction (AFUDC) Equity Revised 2017 Annual True-Up including these changes was posted on Ameren’s OASIS These tariff changes resulted in decreases of $14,165 and $348,591 to the Net Attachment O revenue requirement and Attachment MM revenue requirement, respectively

ROE complaints MISO ROE Complaints RTO Adder (ER15-358) 1st Complaint (EL14-12) Covers November 12, 2013 through February 11, 2015 FERC order received September 28, 2016; set the Base ROE at 10.32% Applicable going forward until 2nd complaint order 2nd Complaint (EL15-45) Covers February 12, 2015 through May 11, 2016 Initial decision issued June 30, 2016; recommended Base ROE at 9.70% Additional refunds may be required upon receipt of Final Order RTO Adder (ER15-358) FERC approved a 50 basis point adder for participation in an RTO Effective January 6, 2015, applicable to complaint case refunds after that date and going forward (i.e., total ROE is now 10.82%)

MISO ROEs for the 2017 True-Up ROE complaints MISO ROEs for the 2017 True-Up 10.82% ROE for January 1 – December 31 Refunds already provided for EL14-12 Two phase process Phase 1 related to ROE impact on projected rates for forward looking TOs and annual updates for historical TOs. These were settled in February 2017. 2013, 2014 & 2015 projected rates from 11/12/13 to 2/11/15 Phase 2 related to the ROE impact on true-ups calculations for forward looking TOs. These were settled in June 2017. 2013, 2014 & 2015 True-ups included in 2015, 2016 and 2017 projected rates Refunds for Schedules 7, 8, 26, 37, 38, 26A were completed by MISO Refunds for Schedule 9 were processed by Ameren Schedule 9 Refund amounts and supporting documents are posted on Ameren’s OASIS

ATXI Revenue Requirement Comparison Projected 2017 vs Actual 2017

Atxi 2017 Rate Base Page.Line 2017 Proj 2017 Act Change Percent 2.6 Total Gross Plant 793,570,602 837,949,452 44,378,850 6% 2.12 Total Accum Depreciation 19,665,259 19,607,016 (58,242) 0% 2.18 TOTAL NET PLANT 773,905,343 818,342,435 44,437,092 2.18a 100% CWIP RECOVERY 506,272,970 462,578,129 (43,694,840) -9% ADJUSTMENTS TO RATE BASE 2.20 Account No. 282 (215,955,048) (174,249,594) 41,705,454 -19% 2.21 Account No. 283 (4,285,216) (2,933,339) 1,351,877 -32% 2.22 Account No. 190 73,283,424 52,581,762 (20,701,663) -28% 2.25 Land Held for Future Use - N/A 2.26 CWC 1,757,484 1,565,210 (192,274) -11% 2.27 Materials & Supplies 2.28 Prepayments 383,153 369,399 (13,754) -4% TOTAL ADJUSTMENTS (144,816,203) (122,666,562) 22,149,641 -15% 2.30 TOTAL RATE BASE 1,135,362,110 1,158,254,003 22,891,893 2%

ATXI 2017 Expenses Page.Line 2017 Proj 2017 Act Change Percent O&M 3.1 Transmission 2,886,648 3,309,758 423,110 15% 3.1a Less LSE Expenses - N/A 3.2 Less Account 565 3.3 A&G 11,173,226 9,211,923 (1,961,302) -18% 3.4 Less FERC Annual Fees 3.5 Less EPRI, ect. 185,211 50,877 (134,334) -73% 3.5a Plus Trans. Reg. Comm. Exp 3.8 TOTAL O&M 14,059,874 12,521,681 (1,538,192) -11% 3.12 TOTAL DEPRECIATION 17,848,671 16,732,540 (1,116,131) -6% TAXES 3.13 Payroll 3.16 Property 1,770,467 2,667,950 897,483 51% 3.18 Other 645,000 460,479 (184,521) -29% 3.27 Income Taxes * 45,932,062 47,381,409 1,449,348 3% TOTAL TAXES 48,347,529 50,509,838 2,162,310 4% TOTAL EXPENSES 80,256,074 79,764,060 (492,014) -1% * The 2017 actual income taxes include the adjustments related to Docket ER17-2323 (discussed on slide 4).

Atxi 2017 capital structure   Actual Capital Structure - 2017 Projection Hypothetical Capital Structure - 2017 Projection Page.Line $ % Cost Weighted Actual Capital Structure Return 7.9914% 4.27 Long Term Debt 461,538,462 44% 4.3495% 1.9014% Hypothetical Capital Structure Return 7.9730% 4.28 Preferred Stock 0% 0.0000% Difference applied to Attachment MM -0.0185% 4.29 Common Stock 594,255,651 56% 10.8200% 6.0901% 4.3 Total 1,055,794,113 100% Actual Capital Structure - 2017 Actual Hypothetical Capital Structure - 2017 Actual 7.6407% 442,307,692 3.5855% 1.5757% 7.6368% -0.0039% 564,164,173 6.0650% 1,006,471,865 Change in Actual Return -0.3507% Change in Hypothetical Return -0.3361%

ATXI 2017 total revenue requirement Page.Line 2017 Proj 2017 Act Change Percent 2.30 TOTAL RATE BASE 1,135,362,110 1,158,254,003 22,891,893 2% 4.30 Rate of Return on ACS 7.99% 7.64% -0.35% -4% 3.28 Return from ACS 90,731,508 88,498,816 (2,232,692) -2% 2.30a 100% CWIP RECOVERY 506,272,970 462,578,129 (43,694,840) -9% 4.30e Incremental Rate of Return on HCS -0.02% 0.00% 0.01% -79% 3.28a Incremental Return from HCS (93,422) (17,953) 75,469 -81% Total Return 90,638,086 88,480,863 (2,157,223) Total Expenses 80,256,074 79,764,060 (492,014) -1% 3.29 TOTAL GROSS REV. REQ. 170,894,160 168,244,923 (2,649,237) 3.30 Less ATT. GG Adjustment - N/A 3.30a Less ATT. MM Adjustment 161,412,747 159,706,197 (1,706,550) 3.31 GROSS REV. REQ. UNDER ATT. O 9,481,413 8,538,726 (942,687) -10%

Atxi 2017 Net Revenue Requirement For Schedule 9 Page.Line 2017 Proj 2017 Act Change Percent 1.1 Gross Revenue Requirement 9,481,413 8,538,726 (942,687) -10% 1.6 Total Revenue Credits 866,750 915,219 48,469 6% 1.6a Historic Year Actual ATRR 9,951,056 (0) 0% 1.6b Projected ATRR from Prior Year 9,757,440 1.6c Prior Year ATRR True-Up 193,616 - 1.6d Prior Year Divisor True-Up 240,319 237,811 (2,508) -1% 1.6e Interest on Prior Year True-Up 3,697 6,206 2,509 68% 1.7 NET REVENUE REQUIREMENT 9,052,295 8,061,139 (991,155) -11%

ATXI 2017 attachment o true up for Schedule 9 Attachment O 2017 True-up calculation (Schedule 9)   Net Actual 2017 Rev Req (Actual Attach O, Pg 1, Line 7) $8,061,139 Net Projected 2017 Rev Req (Projected Attach O, Pg 1, Line 7) $9,052,295 Under/(Over) Collection of 2017 Net Rev Req ($991,156) Historic Year Actual Divisor for Transmission Owner (Attach O, Pg 1, Line 15) 6,859,419 Proj'd Yr Divisor for Transmission Owner (Projected Attach O, Pg 1, Line 15) 7,315,667 Difference between Historic & Projected Yr Divisor 456,248 Prior Year Projected Annual Cost ($ per kw per yr) $1.2374 Under/(Over) Collection of 2017 Divisor True-up $564,561 Total Under/(Over) Recovery ($426,595) Monthly Interest Rate (Over collection = FERC rate, Under collection = company rate) 0.3260% Interest For 24 Months ($33,377) Total 2017 Attachment O True-up Under/(Over) Recovery (To be included in Projected 2019) ($459,972)

ATXI 2017 attachment MM true-up by project

ATXI 2017 attachment MM true-up for Schedule 26-A Attachment MM 2017 True-up (Schedule 26-A)   Actual Attachment MM Rev Req for True-Up Year (Actual Attach MM, pg 2, col 14) 1 $159,706,197 Actual Attachment MM Revenues for 20171 $149,703,040 Under/(Over) Recovery of 2017 MM Rev Req $10,003,157 Monthly Interest Rate (Over collection = FERC rate, Under collection = company rate) 0.0993% Interest For 24 Months $238,395 Total 2017 Attachment MM True-up Under/(Over) Recovery $10,241,552 1 Amount excludes True-Up Adjustment, as reported in True-Up Year projected Attachment MM, page 2, column 15.

Atxi 2017 MVP SPEND Ameren MVPs Ameren Name 2017 CAPEX MTEP #s MTEP Description Illinois Rivers $205 million   2237 Pana - Mt. Zion - Kansas - Sugar Creek 345 kV line 2239 Sidney to Rising 345 kV line 3017 Palmyra-Quincy-Meredosia - Ipava & Meredosia-Pawnee 345 kV Line 3169 Pawnee to Pana - 345 kV Line 3170 New Palmyra Substation (Maywood) Spoon River $56 million 3022 Fargo-Galesburg-Oak Grove 345 kV Line Mark Twain $5 million 2248 Adair - Ottumwa 345 Adair-Palmyra 345 kV Line

MVP Facilities status with In-service Dates Illinois Rivers   Substations Line Segments Kansas Oct-15 Sidney-Rising Sep-16 Sidney Nov-15 Faraday-Pana Oct-16 Rising Herleman-Maywood Pana Meredosia-Herleman Faraday Austin-Meredosia Sep-17 Herleman Pana-Austin Oct-17 Maywood Meredosia-Ipava Dec-17 Meredosia Faraday-Kansas Apr-18 Ipava May-17 Kansas-Sugar Creek 2019 Austin River Crossings Maywood-Herleman Herleman-Meredosia Spoon River Mark Twain Fargo Substation May-16 Zachary Substation Sandburg Substation Mar-17 Maywood-Zachary Sandburg-Fargo Feb-18 Maywood-Ottumwa

Additional information Additional questions can be sent to Ameren at: MISOFormulaRates@ameren.com MISO Web Links Transmission Pricing - Attachments O, GG & MM Information https://www.misoenergy.org/markets-and-operations/ts-pricing Ameren OASIS http://www.oasis.oati.com/AMRN/index.html MTEP 18 https://www.misoenergy.org/planning/transmission-studies-and-reports/#nt=%2Freport-study-analysistype%3AMTEP%2Fmtepdoctype%3AMTEP%20Report%2Fmtepreportyear%3AMTEP18&t=10&p=0&s=&sd= MTEP 17 https://www.misoenergy.org/planning/transmission-studies-and-reports/#nt=%2Freport-study-analysistype%3AMTEP%2Fmtepdoctype%3AMTEP%20Report%2Fmtepreportyear%3AMTEP17&t=10&p=0&s=&sd= Schedule 26 & 26-A Indicative Charges https://www.misoenergy.org/planning/transmission-studies-and-reports/#nt=%2Freport-study-analysistype%3AMTEP%2Fmtepdoctype%3AMTEP%20Study%2Fmtepstudytype%3AIndicative%20Rate%20Reports&t=10&p=0&s=FileName&sd=desc