You generally have 180 days from the date you otherwise would have recognized the gain (i.e., in the absence of an election to defer the gain) to invest in a qualified opportunity fund. In the case of gain that you recognize through a pass-through entity, the starting date for the 180-day period generally can be, at your election, (i) the same date as the pass-through entity (if it were to defer the gain), (ii) the last day of the entity's tax year in which it realizes the gain or (iii) the due date (without extensions) for filing the pass-through's income tax return for such tax year. There's not really any other flexibility (all of the COVID relief has expired).