Retail Electric Suppliers (RES) Portal
Resources and information for Retail Electric Suppliers. If you are a residential, commercial, or industrial customer, please access your usage history data by logging in to Ameren.com.
Welcome to the RES Portal
If you represent a Retail Electric Supplier (RES), an agent for a RES, an Electronic Data interchange (EDI) vendor, or an Aggregator of Retail Customers (ARC), you will need your DUNS number to register for online access to your account(s). If you don't know your DUNS number, please reach out to your Ameren contact for assistance before registering for access.
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Resources and Information for Retail Electric Suppliers
Registration Information
Learn about the requirements to become a registered Retail Electric Supplier.
Learn More
RES Handbook
A guide to conducting business with Ameren in the competitive electric marketplace.
View Handbook (PDF)
Meter Read Dates
View PDFs of scheduled meter read dates for Ameren Illinois and Ameren Missouri.
2025
RES Portal FAQs
Get information about commonly asked questions from scheduled meter read dates, to billing and EDI to transmission and MISO.
See FAQs
Additional Resources
Agency Designation
Learn how a customer can designate and terminate an agency.
Billing Statement Guide
A guide to understanding an Ameren customer's energy statement.
Electric Tariffs
Rate information and service tariffs for Ameren residential electric service.
Energy Supply Options
Learn more about customer energy supply options.
Load Profiles (PDF)
Information on Load Profile Classes assigned to RES customers.
CPWG
Information on the Illinois Communication Protocols Working Group (CPWG).