Copy of Federal Return Required. Failure to attach the required federal copy to the Maryland return shall constitute a nonfiling. Corporations included in a consolidated filing for federal purposes shall attach a copy of pages one through five of the actual consolidated return and shall also provide a copy of the columnar schedule of income and expense, and of balance sheet items, reconciling the separate items of each member corporation to the consolidated totals. Reporting of Internal Revenue Service Adjustments. If at any time the items of federal net taxable income reported for any taxable year or period are adjusted by the Internal Revenue Service (IRS) and will increase Maryland taxable income, a copy of the final IRS adjustment report shall be submitted within 90 days under separate cover. If an affiliated group of corporations files a consolidated federal return, then a copy of the actual IRS adjustment report shall be submitted and shall include a schedule reconciling the separate adjustments for each member corporation. A claim for refund based upon a federal adjustment shall be filed within the time provided under Tax-General Article, §13-1104(c), Annotated Code of Maryland. Notification of a federal audit shall be submitted under separate cover, indicating the corporate name, federal employer identification number, tax year or years involved, and information sufficient to identify the IRS audit and issue or issues. Amended Returns. To correct a previously filed return, the corporation shall file an amended return and provide an explanation and reconciliation of the changes. To claim a net operating loss carryback: The corporation shall attach a copy of the documents required and filed with the IRS; and A member of a consolidated group shall: Attach a copy of any related documents required and filed with the IRS for the group, and Reconcile the deduction claimed for the separate corporation. To claim a refund, the corporation shall file an amended return within the time provided under Tax-General Article, §13-1104(c), Annotated Code of Maryland. Registration of Exempt Organizations. Organizations exempt from taxation under §501 of the Internal Revenue Code shall register with the Comptroller of the Treasury, Revenue Administration Division. An authorized official of the exempt organization shall register the organization by submitting a copy of the Internal Revenue Service determination letter. Estimated Tax. A corporation shall make quarterly estimated tax payments during the tax period if the estimated tax for the complete period will exceed $1,000. Payments of $10,000 or more shall be remitted by immediately available funds pursuant to COMAR 03.01.02. A corporation shall file Form 500D with remittances by the required installment due dates. A declaration of estimated income tax payment shall be due by the 15th day of the 4th, 6th, 9th, and 12th month following the beginning of the tax year or period. The total estimated tax payments for the year shall be at least 90 percent of the tax developed for the current taxable year or 110 percent of the tax developed for the prior tax year. At least 25 percent of the total estimated tax shall be remitted by each of the four installment due dates. For a short tax period, the total estimated tax for the taxable period shall be paid equally over the number of installment due dates occurring during the short tax year. However, estimated tax need not be paid for a short period of less than 4 months. Assessment of interest and penalty for underpayment of estimated tax shall be based on the tax for the current taxable year.