If I'm in a three-property chain and one buyer defaults, what happens to the other two closings?

Each Agreement of Purchase and Sale in your three-property chain is its own separate, binding contract, so a default by one buyer does not automatically excuse the other two closings from proceeding as agreed. The people in the middle of the chain, however, are the ones who feel the practical impact most directly, since they may have been counting on proceeds from their own sale to help fund their own purchase.

If you are caught in the middle, your realistic options generally include arranging short-term bridge financing to cover the shortfall until your own property can be re-sold, negotiating a brief delay with a cooperative counterparty if one exists, or facing default on your own purchase if neither of those can be arranged in time. Whether any of this is achievable depends heavily on how quickly the default is identified and how much flexibility the remaining parties have. Because a default anywhere in a chain puts real pressure on everyone else in it, contact your lawyer the moment you learn of the problem so they can begin working through your specific options immediately.