I am no lawyer, but the short answer I've learned is NO. Until you have all bank signatures on all documents and addenda, the offer is still floating. I would wait until you have it in hand back from the bank signed/delivered before considering it a done deal. AND, if you look closely at the bank lingo in the contract it usually always protects them from everything - meaning they could still pull the rug out from under the deal and decide not to sell it to you for whatever reason they choose. It's the typical limbo REO crap, but you gotta be ready to wear them out and persevere! Good luck!