Integrys Energy Services will become part of Exelon’s Constellation business unit, which serves about 2.5 million residential and business customers in the continental US.
Exelon will pay $60m for the Integrys retail operations and adjusted net working capital upon closing of the transaction.
The transaction does not include Integrys’ energy assets, which will remain a part of Integrys Energy Group.
Integrys Energy Services generated $2bn in annual sales and employed about 280 people as of 31 December 2013.
Integrys Energy Group chairman and CEO Charles Schrock said: "As part of our assessment of Integrys’ portfolio of businesses earlier this year, we determined it was appropriate to divest our retail energy marketing businesses."
The transaction is expected to be completed in fourth quarter of 2014 or first quarter of 2015.
Exelon president and CEO Chris Crane said: "Integrys Energy Services’ geographic footprint is a perfect strategic fit for Constellation and will create opportunities to reach more customers and grow the business, particularly in regions where Exelon also owns significant generation assets."
