Your money is safe — just slow
Failure doesn't put your funds at risk; your intermediary still holds them. But you can't just ask for them back. If you identified nothing by day 45, funds are typically returnable right after day 45. If you identified but didn't close, the exchange agreement generally requires the intermediary to hold funds until day 180 passes (or every identified property becomes impossible to acquire). Bank-vault safe, but locked to the calendar.
The tax outcome
The sale is taxed as an ordinary sale: capital gains, depreciation recapture, state tax — the full bill the exchange would have deferred. The capital gains calculator shows the damage. The exchange fees are sunk, but they're trivial next to the tax.
The year-straddle silver lining
Here's the quirk: if your sale closed late in the year and the failure happened the following year (day 45 or 180 landed after December 31), you constructively receive the money in the new year. Under installment sale rules, you can generally report the gain in the year you received the funds rather than the year you sold — a free one-year deferral. You can also elect to report it in the sale year if that's better (say, lower income that year). One catch: depreciation recapture is generally taxed in the year of sale regardless.
Failing gracefully
If day 40 arrives with no property you'd genuinely buy, don't identify junk to "keep options open" — that locks your money up until day 180 for nothing. Identifying nothing frees the funds sooner. And if you saw it coming, listing a DST as a backup identification is often the better insurance: closable in days, deferral preserved.
Know your exact dates cold →The deadline calculator shows both deadlines and counts down from today