Negative Stock means that you have sold a higher quantity of the products than you had in stock.
We will take the following example:
- We have Coca Cola 0.33, selled in piece.
- At quantity, in Stocks are -13 pieces.
When you are selling one bottle of Coca Cola 0.33, from the current stock will decrease 1 piece, so that you will have -14 pieces in stock.
To reset the stock, it's necessary to add an Invoice on that relative stock.
Also, you can reset the stock by adding a new stock on Inventory.