(a) Every financial institution, as defined in section 1 of chapter 63, shall, on or before the fifteenth day of the fourth month following the close of each taxable year, make a return to the commissioner giving such information as the commissioner considers necessary for the determination of the tax imposed by section 2 of chapter 63.

If any financial institution shall have participated in filing a consolidated return of income to the federal government, it shall file with the commissioner a statement of net income showing its gross income and deductions in accordance with the law and regulations governing the usual federal returns of corporations not so participating.

[There is no paragraph (b) or (c).]