The link below gives the best definition of a "fractional shareholder", as it would apply to this case, as I have seen.
Ownership of an asset by more than one person. The reasons for this approach are many. Allows obtaining an asset beyond the financial capabilities of an individual. Disperses control and accountability of an asset to many owner / managers. Ownership can be don by contract or shares, like stock, of the asset. Sold to individual owners. each owner has the privileges of access to the asset and shares in any resulting income. Any loss allows owners to possibly to claim a tax loss. An example is a vacation homes. The agreement typically has the asset managed by a neutral third-party. The option to sell the asset to minimize loss can be triggered with any resulting monies split among the owners.
Law Dictionary: What is FRACTIONAL OWNERSHIP? definition of FRACTIONAL OWNERSHIP (Black's Law Dictionary)