Can you cure the business's failure to qualify as a QOZB within six months of the failure? If so, the OZ regulations would allow you to treat the QOF's interest in the business as a good QOZB interest on the testing date (but this is a one-time "Mulligan"; your QOF can't get this relief if it's used it before). Alternatively, you could sell the business but you'd have to reinvest the proceeds in a good QOZB by the end of the year (because the 12-month rule that treats reinvested sales proceeds as a good asset applies only if the asset sold is qualified opportunity zone property). Does your QOF have other assets? If so, keep in mind that the 90% test is an average of the two testing dates during the year, so that if the business accounts for less than 20% of the QOF's assets, you might not fail the 90% test (assuming that the other assets are good QOZP and the business was a QOZB at the six month testing date).