A backup offer is a seller's secondary option in case the first offer does not go through. Backup offers are extremely common when the housing market is thriving. Houses do not stay on the market long, and sellers typically have more than one offer submitted simultaneously. In a less-demanding housing market, sellers may still receive a backup offer. For example, two buyers may have viewed a home around the same time and one buyer submits an offer right after the other. The seller is likely to accept the second offer as a backup. Many things can cause a deal to fall through including financing, inspection or just a change of heart. This is why sellers value backup offers. It gives the seller some reassurance that the home will likely sell in the near future, unless both offers fail to go through.