The lists are the product of a new campaign finance law that went into effect July 1. The measure was introduced in response to a controversy surrounding $15 million in contributions funneled through a network of nonprofit groups in 2012.
Committees that have raised at least $1 million to support or oppose ballot measures are required to provide a list of their top 10 donors that gave $10,000 or more to the ethics agency and file updates within 24 hours if that list changes.
The requirements also extend to committees formed to independently support or oppose candidates. Committees controlled by the candidates themselves do not need to report their top donors, although those accounts are subject to strict contribution limits.
Jessica A. Levinson, an election law professor at Loyola Law School, said the format of the top 10 supporters and opponents "is a way of getting the voters cues about what these ballot measures really do."
The law also seeks to curb anonymous political spending by requiring an organization to reveal its donors if it spends or contributes at least $50,000 in one year or more than $100,000 in four consecutive years.