I looked around the site but don't see it posted, and I do not remember from other years - when do the hotels get our info? Thanks!
From the Housing Guide tab (under Attendee Info):
"HOTEL DEPOSIT REQUIREMENTAfter housing registration ends on August 30, 2021, your assigned hotel will charge a non-refundable deposit equal to one night room rate plus tax and convert your assignment into a confirmed hotel reservation. Hotels will begin charging deposits on August 31, but it can take 24 hours or longer for the hotel to complete the transactions and issue confirmed reservations."