These allotments can improve the occupancy of a hotel by enabling Tour Operators, Travel Agents etc. to not only book rooms from their own (limited) allotment, but to book additional rooms from a larger pool of rooms available at individual properties.
Shared allotments consist of a pool of rooms to which a number of Tour Operators, Travel Agents, etc. all have access. They may either use this allotment in case their own allotment is full, or they may not be allocated set number of rooms at all, but simply access the shared allotment whenever they wish to book a room.
Fallback allotments are established to provide a pool of additional rooms for certain customers to “fall-back” upon in case their regular allotments have been used up. During the reservation process, this allotment will come up as the last option.
Exactly who (i.e. which Agent or Operator) is allowed to book within these shared or fallback allotments is determined by the grouping. See also Grouping.