How many times during a year can members receive a transfer of 50,000? The following statement makes it seem like you may only get 50,000 one time a year regardless of whom the points come from:
A limit of 50,000 points per year may be transferred into or out of a member’s account. Members who are transferring points in order to satisfy a specific award may exceed the 50,000 limit up to the amount needed to satisfy the reservation.
The above statement comes from Marriott's site