About Publication 535, Business Expenses Publication 535 discusses common business expenses and explains what is and is not deductible. 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. About Publication 541, Partnerships Information about Publication 541, Partnerships, including recent updates and related forms. Publication 541 explains how the tax law applies to partnerships and to partners. Partnerships pass through profits (losses) to their partners, who must include the partnership items on their tax returns. About Publication 542, Corporations Publication 542 discusses the general tax laws that apply to ordinary domestic corporations. About Publication 550, Investment Income and Expenses Information about Publication 550, Investment Income and Expenses, including recent updates and related forms. Publication 550 discusses the tax treatment of investment income and expenses. About Publication 3402, Taxation of Limited Liability Companies Publication 3402 is used internally by Counsel, walk-in and taxpayer education as well as fed-state. This publication provides federal income, employment, and excise tax information for limited liability companies.