What document summarizes the dividends and capital gains over the tax year for investors?

The document that summarizes the dividends and capital gains over the tax year for investors is Form 1099-DIV. This form is specifically designed for reporting dividends paid and any distributions received from stocks and certain mutual funds. Additionally, it details capital gains distributions, which is particularly relevant for investors who are involved in mutual funds or other investment vehicles that distribute gains to shareholders.

By providing this crucial information, Form 1099-DIV helps investors accurately report their investment income and capital gains on their tax returns, ensuring compliance with tax regulations and accurate calculation of tax liabilities. This form is typically issued by banks and other financial institutions to their customers and is an important document for those who need to report income not derived from wages or salaries.

The other options pertain to different aspects of tax reporting; for instance, Schedule C is used for reporting income from self-employment, Form 1040 is the main individual income tax return form, and Schedule A is for itemized deductions. They do not specifically address the reporting of dividends and capital gains, which makes Form 1099-DIV the most appropriate choice in this context.