PL-300: Microsoft Power BI Data Analyst

None effectively turns off privacy isolation behavior for that source. It does not enforce the Privacy Firewall protections that prevent data from being combined across sources in potentially unsafe ways. While it can reduce firewall errors during development, it increases the risk of unintentionally leaking sensitive values when queries are merged or when folding sends data to another system. Not appropriate for tax records.

Organizational indicates the data is internal to your organization and can be shared/combined with other Organizational sources. It is less restrictive than Private and is designed for typical corporate data where combining sources is acceptable. For highly sensitive tax records, Organizational may still allow combinations that could expose data to other queries or destinations, so it does not meet the requirement to prevent access.

Private is the most restrictive Privacy Level. It isolates the data source so Power Query’s Privacy Firewall prevents other queries/sources from using or receiving data from it through merges, appends, or other cross-source operations that could leak sensitive information. This is the correct setting for tax records or other highly confidential/regulated data to minimize exposure risk.

Public is the least restrictive Privacy Level and is intended for data that is openly available to everyone (for example, public websites or open datasets). Power Query will freely combine Public data with other sources, which is the opposite of what you want for tax records. Setting tax data to Public would increase the chance of accidental exposure through query combinations.