How is capital gains tax reduced in a QOF?

A QOF reduces capital gains tax through two mechanisms: deferring tax on the original gain you invest, and eliminating tax on all new appreciation earned inside the fund if you hold your interest at least 10 years. Neither benefit happens automatically; each depends on timing and documentation that generally requires a supporting valuation.

Deferral of the original gain. When you roll a capital gain into a qualified opportunity fund within 180 days, you defer recognizing that gain until you dispose of the QOF interest or December 31, 2026, whichever comes first. That deferred gain is eventually taxed, but the 10% and 15% basis step-ups that once permanently reduced it applied only to investments made before the end of 2021 and held for 5 or 7 years, so they're no longer available to new investors.

Elimination of tax on new appreciation. This is the benefit still fully in play: if you hold your QOF interest for at least 10 years, you can elect to step up your basis to fair market value at disposition. Any growth the fund generated during your holding period is never taxed. This is the piece of IRC 1400Z-2 that makes long-term QOF investment attractive even now that the deferral window is closing.

Because both the 2026 inclusion event and the eventual 10-year exit depend on knowing your interest's fair market value, an accurate, well-documented valuation matters at each step. A qualified opportunity fund valuation establishes the basis figures your CPA or tax attorney needs to report the deferred gain correctly and to support the eventual basis step-up at sale.

For more on the mechanics and timing involved, see our answers on what happens to Opportunity Zones after 2026 and how long you must hold a QOF investment.