Delaware Administrative Code
Title 5 - Banking
1100 - Taxation
1101 - Election to Be Treated for Tax Purposes as a "Subsidiary Corporation" of a Delaware Chartered Banking Organization or Trust Company, National Bank Having its Principal Office in Delaware, or Out-of-State Bank That Operates a Resulting Branch in Delaware
Section 1101-4.0 - When to Make the Election

4.1 The election must be made and filed before the first day of the fourth month of the Electing Corporation's taxable year, except that, (1) in the case of a corporation that is newly formed or acquired by the Qualifying Entity, the election may be made and filed within 90 days of such formation or acquisition, and such later election shall not be subject to the payment of any additional tax under 5 Del.C. § 1104 (c) for underpayment of estimated tax or installment for periods before the date of such election, and (2) with the approval of the Commissioner, a later election may be made, subject to the payment of any additional tax for underpayment of estimated tax or installment as provided in 5 Del.C. § 1104 (c) and applicable regulations of the Commissioner.