If there is an amount in Box 5 of your 1099 DIV form, it will be used in the QBI deduction calculation as 20% of qualified REIT dividends are included. See the attached 1099 DIV form and box 5 instructions below. Also see the IRS QBI calculation worksheet which includes the qualified REIT dividends.
Per the IRS recently released
Notice 2019-07, the following is a definition of the income included in the QBI deduction calculation:
Congress enacted section 199A (the Qualified Business Income Deduction) to provide a deduction to non-corporate
taxpayers of up to 20 percent of the taxpayer’s qualified business income from each of
the taxpayer’s qualified trades or businesses, including those operated through a
partnership, S corporation, or sole proprietorship, as well as a deduction of up to 20
percent of aggregate real estate investment trust (REIT) dividends and qualified publicly
traded partnership income.