Ohio Rev. Code § 4909.42
If the proceeding on an application filed with the public utilities commission under section 4909.18 of the Revised Code by any public utility requesting an increase on any rate, joint rate, toll, classification, charge, or rental or requesting a change in a regulation or practice affecting the same has not been concluded and an order entered pursuant to section 4909.19 of the Revised Code at the expiration of two hundred seventy-five days from the date of filing the application, an increase not to exceed the proposed increase shall go into effect upon the filing of a bond or a letter of credit by the public utility. The bond or letter of credit shall be filed with the commission and shall be payable to the state for the use and benefit of the customers affected by the proposed increase or change.
An affidavit attached to the bond or letter of credit must be signed by two of the officers of the utility, under oath, and must contain a promise on behalf of the utility to refund any amounts collected by the utility over the rate, joint rate, toll, classification, charge, or rental, as determined in the final order of the commission. All refunds shall include interest at the rate stated in section 1343.03 of the Revised Code. The refund shall be in the form of a temporary reduction in rates following the final order of the commission, and shall be accomplished in such manner as shall be prescribed by the commission in its final order. The commission shall exercise continuing and exclusive jurisdiction over such refunds.
If the public utilities commission has not entered a final order within five hundred forty-five days from the date of the filing of an application for an increase in rates under section 4909.18 of the Revised Code, a public utility shall have no obligation to make a refund of amounts collected after the five hundred forty-fifth day which exceed the amounts authorized by the commission's final order.
Nothing in this section shall be construed to mitigate any duty of the commission to issue a final order under section 4909.19 of the Revised Code.
R.C. § 4909.42