Switching to a Supplier 

A Supplier may contact a prospective customer by phone, by mail, or in-person. If a customer wishes to contact a Supplier, a list of Suppliers registered with Ameren Illinois and certified by the Illinois Commerce Commission to supply commercial and industrial accounts can be found on the Suppliers Registered with Ameren page.

When a customer is considering switching to a Supplier, the Supplier will ask the customer for certain pieces of information (e.g. name, billing address, service address, Ameren Illinois account number, meter number). The customer should provide this information to a Supplier if the customer is interested in switching to the Supplier’s service. The switch to a Supplier cannot be completed until all terms and conditions have been explained, and the customer has provided authorization for the switch. The valid forms of authorization are a written signature, electronic signature, or a recorded third party verification performed over the phone. Once a customer has agreed to switch to a Supplier, the Supplier will submit an electronic enrollment transaction to Ameren Illinois. If the enrollment transaction is accepted (i.e. it contains a valid account number), Ameren Illinois is authorized to release a range of customer data to that Supplier, including the customer’s historic and ongoing electricity usage data.

Customer Information

Once an enrollment to a Supplier is effective, the Supplier will begin receiving ongoing monthly usage data. A customer may also request, or the Supplier may request per a separate written authorization from the customer, billing data including revenues and payment history.

An Ameren Illinois account number is the validation criteria needed for a Supplier to enroll a customer’s account. This means that the Supplier must have this number correct in order to successfully submit the enrollment to Ameren Illinois. A customer should not give an account number to a Supplier unless the customer is considering switching to the Supplier.

Ameren Illinois will not accept personal information changes to a customer’s account from a Supplier unless the customer has signed an Agency Agreement designating the Supplier as the customer’s agent.

Effective Date of Enrollment to a Supplier
An enrollment will take place on a customer’s account’s next scheduled meter reading date and in accordance with the terms of the contract with the Supplier.

Ameren Illinois will honor the first enrollment request received from a Supplier. If Ameren Illinois receives a second enrollment request from another Supplier before the first enrollment is activated, then the second enrollment request will be rejected.

The enrollment transaction from the Supplier must be processed by Ameren at least ten calendar days plus two business days (but no more than 45 calendar days) prior to the account’s next scheduled meter reading date.


When a Supplier submits a valid enrollment request to Ameren Illinois, Ameren Illinois will send a letter notifying the customer of the impending enrollment. If the enrollment information on the notification letter is incorrect, or if the customer has changed his/her mind regarding the enrollment, then the customer must notify Ameren Illinois as soon as possible. Specifically, the customer has ten calendar days from the date that Ameren Illinois processes the Supplier’s enrollment to contact Ameren Illinois and request a rescission of the pending enrollment. The last day of the ten calendar day rescission window is stated in the customer enrollment letter. Note that a Supplier may assess a fee to the customer for rescinding the Supplier’s enrollment.

Loss of Service

Ameren Illinois has no responsibility for claims, damages or losses resulting from a customer’s relationship with a Supplier regarding delivery or non-delivery of energy or energy services.

If the Illinois Commerce Commission revokes a Supplier’s certificate or the supplier materially defaults in its service agreement, then Ameren Illinois will notify that Supplier’s customers as quickly as possible regarding the change and the available supply options.

If a Supplier stops doing business, then that Supplier’s residential accounts will be placed on Ameren Illinois BGS supply.

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