Contract design and stability in many-to-many matching

In many-to-many matching with contracts, a new market design issue arises: The design of the contract language can impact the set of stable outcomes. Bundling contractual primitives encourages substitutability of agents' preferences over contracts and makes stable outcomes more likely to exist; however, bundling also makes the contractual language less expressive. Consequently, in choosing contract language, market designers face a tradeoff between expressiveness and stability.