What date you report depends on the policy at your institution. The last bank that I worked for reported the date the borrower signed (not the date printed next to the loan officer's name by the LOS) for the application date on third party applications. Where I currently work, we report the date that our institution received the application in our underwriting department. Either of these are acceptable, though I prefer the current policy I am working under. Consistency in your reporting is what counts. Remember, the broker may have shopped the loan around for months to different lenders before it arrived at your institution.