For the purposes of simplicity, you can consider any entity that is comprised of data within your organization as a data asset. You may choose to ascribe economic value to this asset or not, depending on the scarcity or significance of that data asset to your business.
In the context of the Pretectum CMDM; the supporting sets of data that constitute Business Area Data can be considered as data assets, as can the meta definitions found in the Schema definitions and the schema fields that you have within Business Areas.
In addition, you can consider the actual datasets that are contained within the various schemas as your data assets and the individual records that describe customers as data assets too.