buying shortsale and re-applying for pre-approval

It will effect your scores, however it will be minimal... your lender will pull your credit the day they are ready to fund as well.. they are checking to be sure no bad credit has popped up, you haven't abused your credit cards, and you didn't take on any additional debt which in turn would raise your debt to income ratios... This is normal... WilliamAcres.com

Assuming your credit was acceptable at the time of the initial application, there is no need for them to pull it again until you submit the accepted contract. At our organization, once the borrower is pre-qualified and begins the shopping process (short sale or otherwise), we do not re-pull until the file becomes "Active" with the submission of a contract. There is no real reason for them to automatically pull credit every 90 days. It is true that the credit report "expires" after 90 days with most lenders, but having 3 expired reports in a file just because it took the short sale lender 6 months to agree to the sale does not accomplish anything. Your file with the lender should be sitting in "Pending" until they receive the contract. If they are telling you that they have to do this, I think you are working with the wrong lender. If you are using one of the "Banks", they probably require this as their policy to make sure their pending files are still viable.

The fear of reduced credit scores with the occasional pull from a creditor is the most annoying, misleading, and misunderstood thing I hear every week. If you are worried about "inquiries on your report", this isn't the concern most people think it is. Visit http://www.myfico.com/crediteducation/creditinquiries.aspx to find out the truth about inquiries and your credit score. 99% of people should have absolutely NO CONCERN whatsoever about inquiries.