Form 1128, Application To Adopt, Change, or Retain a Tax Year
File this form to request a change in tax year. Partnerships, S corporations, personal service corporations (PSCs), or trusts may be required to file the form to adopt or retain a certain tax year.
Form 3115, Application for Change in Accounting Method
File this form to request a change in either an overall method of accounting or the accounting treatment of any item.
Publication 509, Tax Calendars
This publication has three tax calendars with specific due dates for: filing tax forms, paying taxes, and taking other actions required by federal tax law.
Publication 535, Business Expenses
This publication discusses common business expenses and explains what is and is not deductible. The chapters cover general rules for deducting business expenses and specific expenses.
Publication 537, Installment Sales
This publication discusses the general rules that apply to using the installment method and more complex rules when certain conditions exist or certain types of property are sold.
Publication 538, Accounting Periods and Methods
This publication explains some of the rules for accounting periods and accounting methods. It is not intended as a guide to general business and tax accounting rules.
Publication 946, How To Depreciate Property
This publication explains how you can recover the cost of business or income-producing property through deductions for depreciation.