There are a lot of things that can dictate the closing date. Most of the time it is the lender. Sometimes the challenge is in getting an answer back from the third party (bank) when you place an offer on a short sale. I have had short sales where the offer was accepted in 3 days and it closed in 30 days but I have also had short sales where a decision was not made for the months. The main point is that there are various challenges which can come up during the process which could derail any timeline. This is why it is important to have a good agent to help you through this process.