Sponsor unit

It means the owner of the building owns that unit that is for sale or rent.

It means that a board of strangers won't have to decide if you are good enough to live in their building.

It's a good thing.

The shares for that apartment are owned by the former owner of the whole building. She/he/it is called the sponsor or Holder of Unsold Shares.

When the sponsor converted the building to a co-op, that apartment's tenant chose to remain a tenant of the sponsor rather than buy shares in the new cooperative corporation. Now that tenant has died or otherwise vacated, and the sponsor is free to sell the shares and apartment. That sale is not subject to the approval of the co-op's board.

That's the typical scenario.

In addition to any premium for avoiding the board process, you'll also pay the NYS/NYC taxes that're usually paid by the seller, so add those in when calculating an offer.

Thanks. Very, very helpful.