(220 ILCS 30/10.7) (from Ch. 111 2/3, par. 410.7)

Sec. 10.7. Penalties for underpayment; enforcement. Each payment of the tax imposed by Section 10.3 becomes delinquent at midnight of the date that it is due. In the event that upon the filing of an amended return pursuant to Section 10.5 of this Act it appears that an electric supplier has failed to pay or has underpaid the proper amount of tax due, it shall pay a penalty to the Commission of 1% of the amount so due for each month or fraction thereof that such amount is unpaid. The Commission may enforce the collection of any delinquent payment, or portion thereof by legal action or in any other manner by which the collection of debts due the State of Illinois may be enforced under the laws of this State.

(Source: Laws 1967, p. 659.)