By March 10, the political parties and coalitions participating at the 2021 Parliamentary elections must submit the information under article 171, paragraph 2 of the Electoral Code to the Unified Register for Election Participants with the National Audit Office.

The political formations must announce the full names, personal identification number and address of their donors, as well as the type, purpose and amount of donations. They must also announce the names of the legal persons and the sole proprietors, as well as the type, purpose and amount of their donations. If donations exceed the amount of the minimum monthly salary in Bulgaria, the origin of the funds must be declared. The political parties and coalitions also declare the names of the sociological, advertising agencies and PR agencies they work with.