To purchase a Leasehold, otherwise known as Trapasos in Spain, means that you are buying the right to occupy the land or building for a determined amount of time.
The amount of time that leasehold contract runs for is normally between 5-10 years, this can of course be renewed subject to agreement with your Landlord.
The main advantage of purchasing a leasehold property in Spain is the financial implications. Buying a leasehold costs a fraction of the price than to purchase the property outright.
The second advantage, if for whatever reason the business is not a success, or your circumstances change, you can sell on the Leasehold (Traspaso) to a third party. Thus releasing you from your financial burden.
One disadvantage of purchasing a leasehold is that it is not forever. As the lease contract only lasts for between 5-10 years, there is the possibility that the leasehold may not be renewed.
Secondly, the fact that you do not own the building outright means that you cannot use it for financial assistance if needed. There may also be restrictions on what you can and cannot do to the building. You will need to gain permission from the landlord before any works to the property are carried out.