In most co-ops, board approval is necessary to sublet an apartment. Board of Managers . Elected by the condo's shareholders, this group runs the joint. Theoretically, these guys have the right of first refusal in accepting a tenant for residence, but they rarely use it. Apartments in condominiums are individually owned, but tenants share responsibility for and ownership of all common areas, e.g. laundry room, lobby, elevators, hallways, etc.
Renters deal directly with the building owner or manager.
Co-ops are owned by a corporation and operated for all persons living in the building. Apartments in co-ops are generally owned by shareholders in the corporation, but can be sublet to outside parties. All tenants must be approved by the Board of Directors. Guarantors substitute for bad credit or low income and assume all responsibility for rent should the primary renter default. Usually, guarantors must earn 75 times one month's rent.