The “split” option determines the quantities of tickets that a customer may purchase out of your group of tickets.  There are three different options for your ticket listing:

Smart: Buyers can purchase your tickets in varying quantities, but you will never be left with a single ticket.

Any: Buyers can purchase any amount, which may leave you with a single ticket.

None: Buyers must purchase all of the tickets together.

Note: 

You can always update your chosen split by signing-in to your Vivid Seats account, navigating to the listing in the Listing Manager, and clicking "Edit Listing." If you’re listing tickets with the attribute of ‘Aisle seat,’ the split type is automatically set to “None” and cannot be changed. If you’re only listing one ticket for sale, you won’t be asked to set a split.