| Case Number | Case Title | Open Date | Closed Date |
| 03-0681-EL-COI | COMMISSION INVESTIGATION INTO ELECTRIC ANCILLARY SERVICES | 03/11/2003 | |
| 03-2325-EL-COI | FIRSTENERGY CORPORATION | 11/24/2003 | |
| 09-0090-EL-COI | IN THE MATTER OF THE COMMISSION'S INVESTIGATION INTO THE VALUE OF CONTINUED PARTICIPATION IN REGIONAL TRANSMISSION ORGANIZATIONS | 03/02/2009 | |
| 12-0150-EL-COI | THE COMMISSIONS INVESTIGATION OF DYNAMIC PRICING OPTIONS FOR RETAIL ELECTRIC SERVICES | 01/04/2012 | |
| 12-3151-EL-COI | In the matter of the Commission's Investigation of Ohio's Retail Electric Service Market | 12/07/2012 | |
| 14-0568-EL-COI | IN THE MATTER OF THE COMMISSION ORDERED INVESTIGATION OF MARKETING PRACTICES IN THE COMPETITIVE RETAIL ELECTRIC SERVICE MARKET | 04/08/2014 | |
| 20-0434-EL-COI | IN THE MATTER OF THE COMMISSION'S INVESTIGATION INTO ELECTRIC VEHICLE CHARGING SERVICE IN THE STATE. | 02/25/2020 | |
| 96-0406-EL-COI | CONJUNCTIVE ELECTRIC GUIDELINES | 04/29/1996 | |
| 97-1146-EL-COI | CLEVELAND ELECTRIC ILLUMINATING | 09/25/1997 | |
| 97-1147-EL-COI | TOLEDO EDISON COMPANY | 09/25/1997 | |
| 99-0190-EL-COI | ELECTRIC GENERATION/INVESTOR-OWNED | 02/25/1999 | |
| 99-0191-EL-COI | ELECTRIC TRANSMISSION/INVESTOR-OWNE | 02/25/1999 | |