The IRS issued proposed reliance regulations that explain how taxpayers can elect to aggregate their trades or businesses for purposes of limitations on the qualified business income (QBI) deduction (also called the pass-through or Section 199A deduction). The IRS explained that, if certain requirements are met, individuals who engage in more than one trade or business may (but aren’t required to) aggregate them, treating them as a single trade or business. The new deduction allows sole proprietors, partnerships and S corps to write off 20% of their QBI.