From the IRS e-News for Tax Professionals Issue 2019-35, dated September 27, 2019:

The IRS this week issued Revenue Procedure 2019-38, which establishes a safe harbor allowing certain interests in rental real estate, including interests in mixed-use property, to be treated as a trade or business for purposes of the qualified business income deduction under section 199A of the Internal Revenue Code.

The safe harbor is available for individuals who claim the section 199A deduction with respect to a “rental real estate enterprise.” To review the qualification requirements, visit IRS.gov/taxreform.

Note: there is still much argument out there over whether the safe harbor is intended to be seen as a definition of a rental real estate trade or business, or simply a minimum requirement in order to avoid having to prove whether or not an activity qualifies under section 162. Safe harbors sometimes get used in the code more like a definition — and sometimes they are seen as… well, as more of a safe harbor.

Some educators are taking the stance that even if a real estate rental regularly has losses, if they otherwise qualify under section 162 as a trade or business, they must include these losses as 199A regardless of meeting the safe harbor. Of course, this could negatively affect their clients. Other educators are taking the stance that these small rental real estate clients who regularly have losses and have no incentive to qualify under 199A can avoid it precisely because they do not meet the safe harbor (as if the safe harbor were a definition of a trade or business). Only time and the courts will tell whose interpretation will prevail.