The declaration of estimated tax shall be on Form D-40ES. The form may be obtained from the Deputy Chief Financial Officer. The form shall be executed and filed in accordance with the instructions on the form.
For the purpose of making a declaration, the amount of gross income which the taxpayer can reasonably be expected to receive or accrue (as the case may be, depending upon the method accounting used to compute net income); and the amount of the estimated allowable deduction, personal exemptions, and credit for dependents to be taken into account in computing the amount of the estimated tax shall be determined on the basis of facts and circumstances existing at the time prescribed for the filing of the declaration.
The declaration shall contain the following:
An amended declaration may be made in any case in which the taxpayer estimates that gross income, deductions, or credits will differ from the gross income, deductions, or credits reflected in the previous declaration.
An amended declaration may also be made based upon a change in the number of exemption to which the taxpayer may be entitled for the then current year.
Amended declarations shall be on Form D-40ES and marked "AMENDED."
No amended declaration may be filed during the quarterly period in which the original declaration was filed. Only one (1) amended declaration may be filed in any quarterly period subsequent to the quarterly period during which the original declaration was made.
In the case of a taxpayer on the calendar year basis, if an original declaration was previously filed, an amended declaration which is to be filed after September 15th may be filed on or before January 15th of the succeeding calendar year.
In the case of a taxpayer on the fiscal year basis, if an original declaration has previously been filed, an amended declaration which is to be filed after the 15th day of the ninth month of that fiscal year may be filed on or before the 15th day of the first month of the succeeding fiscal year.
D.C. Mun. Regs. tit. 9, r. 9-145