Otherwise, there is no set time frame where the bank must respond. I have literally seen short sales take anywhere from 30 days (that was with a very small bank) to over 2 years. You can read more about why here:
Hope this helps!
Berkshire Hathaway HomeServices
The Tonnesen Team - with over 30 years of experience helping families call Las Vegas "home!"
Yes, you need to write an offer that allows you to back out if you get tired of waiting, but if you hang in there, short sales are a great way to get a deal.
A properly written contract for your short sale purchase has timelines in it. Depending on how your's was written you may be able to walk away anytime or be obligated for a period of time. Lenders have their own timetable and will not be motivated by anything you, the seller's or the agents do to speed things up. Seller's can slow the process down if they don't cooperate and provide necessary documentation in a timely manner.
Start by reviewing your contract or asking your agent. Next, regardless of what the contract says, keep your eyes open as if the right opportunity comes along, it may be worth losing your earnest money, which is typically the only thing you have at risk.
I've had short sales take 3 months, I've had them take 19 months. No two are the same. I wrote a blog piece attached below regarding all that's involved with getting a short sale approved, it may be helpful to you.