  In many real-world matching applications, there are restrictions for
institutions either on priorities of their slots or on the transferability of
unfilled slots over others (or both). Motivated by the need in such real-life
matching problems, this paper formulates a family of practical choice rules,
slot-specific priorities with capacity transfers (SSPwCT). These practical
rules invoke both slot-specific priorities structure and transferability of
vacant slots. We show that the cumulative offer mechanism (COM) is stable,
strategy-proof and respects improvements with regards to SSPwCT choice rules.
Transferring the capacity of one more unfilled slot, while all else is
constant, leads to strategy-proof Pareto improvement of the COM. Following
Kominer's (2020) formulation, we also provide comparative static results for
expansion of branch capacity and addition of new contracts in the SSPwCT
framework. Our results have implications for resource allocation problems with
diversity considerations.
