Most gliders are privately owned, and most of those are in what you call equity groups (usually termed glider syndicates in our world). A smaller number, but growing, are single ownership.
To add, an important reason for sharing the ownership, but also the operation of a glider between (at least) two persons is to have somebody on the ground to come and fetch you with the trailer if you land "out".
With single ownership you always have to make arrangements before every flight just in case this happens.