IRS 1099 forms are used to report interest, dividends, royalties, and freelance earnings. Experts estimate that over 10% of 1099 forms contain some type of error. If you file your taxes based on an incorrect 1099 you could have to file an amended return − or worse pay a penalty on unreported income. Compare your 1099s to bank and brokerage statements; if you find an error, ask the company to send you and the IRS a revised copy. The IRS will compare your tax return information with the 1099 information it receives, so always make sure the numbers match. (Great advice for any numbers you report on your tax returns.)