A double close only works if the closing agent will fund the first closing from the second buyer's money, and that has to be confirmed in writing first
Take a small three bedroom under contract at 91k with an end buyer lined up at 118k. A double close is often chosen over an assignment when a spread like 27k looks large enough to make the end buyer come back and renegotiate, since taking title keeps the two prices separate. The mistake that sinks deals like this is never asking the closing agent, in plain words, whether they will fund the first closing out of the second buyer's proceeds. That is not standard everywhere. Some closers will not disburse one file's proceeds into another file, meaning the purchase has to be funded independently of the resale. When that happens close to the seller's deadline, the wholesaler suddenly needs the full purchase price plus costs for a matter of hours. Transactional funders can sometimes work on price, roughly 2 points plus a doc fee around 1,495, but they typically want the resale contract and proof the end buyer can close, and a resale contract with a financing contingency and a lender unwilling to confirm anything in writing inside a week kills that option fast. Smaller funders often will not quote a loan under 100k at all. An extension request at that point depends entirely on how much goodwill is left with the seller, and a seller who has already granted one extension for inspection, with a backup offer in hand, is unlikely to grant a second. A loss in a situation like this typically runs into the thousands: earnest money that has gone hard, an inspection fee, an attorney review fee, none of it recoverable. The lesson is to get the closing agent's policy on back to back funding in writing before signing the purchase contract, and to have a transactional funder pre-approved ahead of time so their answer does not decide the deal at the last minute. A large spread is also a reason to plan the funding path carefully, not a reason to keep the number quiet.