For fiscal year business taxpayers:

Annual Final Return is due within 4 months of the end of the fiscal year. See Ord. 181.05(a).

For taxpayers with extensions to file:

Upon approval of the Tax Administrator, not to exceed six months or one month beyond any extension granted by the Internal Revenue Service for the filing of the Federal income tax return. Note: requests for extensions must filed by the date the annual return was due and must be accompanied by the payment of at least eighty percent (80%) of the amount of estimated tax shown to be due thereon. See Ord. 181.05(c).