The circular provides guidance on corporate income tax incentives and deductions in Vietnam. It reintroduces tax incentives for certain industrial zones and changes incentives for new projects and business expansions. For deductions, it increases the cap on advertising expenses from 10% to 15% of expenses and makes other changes such as capping casino expenses and restricting education deductions. The circular also clarifies treatment of unrealized gains, advertising expenses for real estate, transfer pricing documentation, and prorated tax rates for non-December year-ends.