Ameren Missouri Rate Increase: $13 a Month Asked for 2027

Ameren Missouri is asking state regulators to raise its electric base rates by about $343 million a year. Ameren says the average residential bill, for a home using 1,011 kWh a month, would rise by about $13 a month if the request is approved as filed. The Missouri Public Service Commission (PSC) has not ruled, and Ameren expects new rates in mid-2027, after a PSC review it puts at 11 months.

The case is ER-2026-0291, filed June 26, 2026. It covers Ameren Missouri’s roughly 1.1 million residential electric customers, including customers in the St. Louis area. For Evergy’s pending case and the rest of the state, see our Missouri electric rates and solar overview.

The Request at a Glance

What Ameren Is Asking For

Ameren’s cover letter says its proposed tariffs are designed to raise “electric base rate annual revenues by approximately $343 million.” The filing’s summary schedule puts the total at $342,883,000, or “an overall increase of approximately 10.4% on a pro forma basis.”

Homes would carry about half of that. The filing assigns $171.2 million of the increase to residential service, a 10.2% rise for the class. Spread over 1,107,969 residential customers, Ameren puts the average change at $154.53 a year, or about $12.88 a month. Separately, Ameren estimates about $13 a month for a home using 1,011 kWh.

What the 10.2% implies about today’s bill. If $154.53 is 10.2% of the average residential customer’s annual bill, that bill is about $1,515 a year today, or roughly $126 a month. That is our calculation from Ameren’s two figures, not a number Ameren published, and your bill depends on your own usage.

The filing uses a test year of the 12 months ending March 31, 2026, with costs updated (“trued up”) through December 31, 2026. That means the final figure can move as Ameren’s actual costs through the end of this year are reviewed.

Ameren gives these reasons in its June 26 announcement:

• Storm hardening and grid upgrades: rebuilding lines in North St. Louis and Southeast Missouri after the spring 2025 tornadoes and storms, plus new and upgraded substations and stronger utility poles. Ameren says this kind of work “helped prevent more than 260,000 customer outages” from January 2025 through May 2026.
• Generation: work at the Labadie Energy Center, upgrading the Audrain Energy Center to run on two fuels in extreme weather, and “400 megawatts of new generation” from three new energy centers expected online by the end of 2026.
• Data centers: Ameren says it “is not currently serving any large load data center customers” and that the costs of serving announced data centers are not driving this request. The filing adds a separate large-load customer class, as the PSC ordered in an earlier case (ET-2025-0184).

Ameren also says its residential rates are about 27% below Midwest and national averages, citing an Edison Electric Institute report through June 30, 2025. We have not checked that comparison independently.

Fuel costs stay on a separate track. The filing says 95% of future changes in Ameren’s net energy costs will still pass through its fuel adjustment clause. So fuel-driven bill changes can arrive between rate cases, up or down.

A Proposed Discount for Lower-Income Households

Ameren’s release says it is “establishing a new income-eligible discount rate” meant to offset the increase for the customers who can least afford it. According to St. Louis Public Radio, the proposal would give 20% off to households under 150% of the federal poverty line and 10% off to other eligible customers. The Consumers Council of Missouri told the station it was still reviewing how the relief plan is structured. The PSC has not ruled on the discount, and the eligibility details may change.

Where the Case Stands

The PSC’s case calendar sets out the steps. As of October 27, 2026, we found no settlement and no decision.

The December 4 filing is the first point where the PSC’s staff and other parties, such as consumer advocates, are scheduled to put their own revenue numbers on the record. Those figures can be well below what a utility requests. In Ameren’s last electric case, the PSC approved an agreement for $355 million on April 23, 2025, after Ameren asked for $446 million. The outcome of this case is not known.

The calendar also lists local public hearings, but we could not confirm their dates, so check the PSC’s announcements. To comment, KFVS reported the PSC’s channels: email [email protected], call 800-392-4211, or write to P.O. Box 360, Jefferson City, MO 65102, citing ER-2026-0291.

What It Means for Your Bill and for Solar

For most households: an increase near $13 a month would not start until mid-2027 if approved. The split matters as much as the total. The December 18 rate design testimony will show whether more of the increase lands on the fixed customer charge (now $9 a month for residential customers, unchanged in the 2025 case; we have not checked whether this filing proposes a change) or on per-kWh charges. Our guide to reading your electric bill shows where each line appears.

For solar owners and shoppers: Ameren credits solar in two ways. Solar you use at home avoids buying power at the retail rate. Surplus beyond your usage earns an avoided-cost credit, which Ameren lists at 3.84¢ per kWh in summer (June to September) and 3.39¢ in winter (October to May). Net metering applies to systems of 100 kW or less.

So a base rate increase helps solar in one place: every kWh you produce and use yourself becomes worth more. It does little for surplus. A system sized so production stays near or below your monthly use gets the most from higher rates. If more of the increase goes into the fixed charge, solar offsets less of it, as we explain in fixed charges and solar savings.

If you are getting solar quotes now, ask the installer which Ameren rates the savings estimate assumes. A quote built on today’s rates may understate savings if the increase is approved, and a quote that assumes the full request may overstate them.

What to Watch

1. December 4, 2026: the first testimony from the PSC staff and other parties on how much of the $343 million is justified.
2. December 18, 2026: rate design, including any change to the $9 customer charge.
3. Spring 2027: a settlement or a PSC order, with new rates expected in mid-2027.

For how these steps fit together, see how electric rate cases work.

Limitations

The $13 a month figure is Ameren’s estimate for a home using 1,011 kWh. The details of the income-eligible discount come from a news report of the proposal, not the tariff itself. We could not open the PSC’s suspension order, and the local public hearing dates on the case calendar could not be confirmed. Ameren’s rate comparison with Midwest and national averages is the company’s claim.

Sources and verification

Checked October 27, 2026. Figures in the rate case are requests, not approved rates.