Bundles are non-stock tracked products and do not hold a stock level of their own.
However as they are made up of stock tracked components, they do have an availability, which manifests as an on hand level.
This quantity is calculated based on the maximum number of bundles that could be made with the current on hand inventory of the components.
For example, take a bundle with 2 components:
1 x Product A
2 x Product B
In order for 1 x Bundle X to be made, there needs to be 1 unit of Product A and 2 units of Product B on hand.
If there were 15 units of Product A in stock and 20 units of Product B in stock, the bundle availability would be 10:
Bundles and multiple warehouses
If there are multiple warehouses involved, the bundle availability is calculated per warehouse.
i.e. if there were 10 units of Product A in Warehouse One and 20 units of Product B in Warehouse Two, the bundle availability of Bundle X would be zero, because no bundles could be made in either warehouse.
In the above example, there are 5 units of Product A and 7 units of Product B in total.
If they had been in the same warehouse, they would have been able to make 3 bundles.
However, because of the way they are split between warehouses, they can only make 2 bundles - one in each warehouse.