The stock assigned to the marketplace will always be the one defined by the seller, because the marketplace will always consult the available stock on the seller area.

This stock may be the same used by the main store or another one specific for a marketplace, or for more than one marketplaces, with different rules and prices setup.

All these configurations are possible to be set in the commercial policy.

This option will be chosen if you want to configure the marketplace to use the same logistics configuration of the main store or of another marketplace.

This means that the marketplace doesn't demand a special term or price, then, there is no need for a new configuration.

So, simply join the same commercial policy to the new marketplace.

This means that different terms and prices than all other settings used in the store will be practiced. Therefore, you need to set up a new commercial policy and a new logistics rule for the marketplace.