Laure_boi, they don't have any set time frame. It depends upon the case. Sometimes they keep asking for more information and that delays the approval. If you do premium processing (I think it costs an extra $1000) I think they will get back to you in 15 days. Otherwise, it could take anywhere from 1 to 6 months. However, this year they don't have a lot of applications so may be that will speed up the process. This blog http://www.happyschoolsblog.com/ usually has good information on this topic.