Del. Code tit. 5 § 1109
Notwithstanding Title 30, all banking organizations, trust companies and federal savings banks not headquartered in this State but maintaining branches in this State being taxed in accordance with this chapter, shall be exempt from the state corporation income tax as of January 1, 1974, and the taxation of income of banking organizations, trust companies and federal savings banks not headquartered in this State but maintaining branches in this State under this chapter shall be in lieu of occupational taxes or taxes upon the income, capital, and assets of such banking organization, trust company or federal savings bank not headquartered in this State but maintaining branches in this State, except that no real estate owned or acquired by such banking organization, trust company or federal savings bank not headquartered in this State but maintaining branches in this State shall be exempt from taxation. Except for corporations making the election provided in § 1101(e) of this title, for purposes of this section, any subsidiary corporation of a banking organization or trust company, including any corporation treated as a subsidiary corporation by reason of § 1101(f) of this title, shall enjoy the same exemptions as are applicable to banking organizations and trust companies. A subsidiary corporation or a division of a bank or trust company engaged in activities authorized under § 761(a)(14) or § 1661(a)(14) of this title shall be taxed in the same manner as an entity engaged in such activities pursuant to Title 18.
5 Del. C. § 1109