Australia's competition regulator has started work on its inquiry into the digital advertising supply chain.

Responses are due by April 21 to an issues paper which seeks views on key issues. Accompanying the issues paper on markets for the supply of digital advertising technology services and digital advertising agency services, are two two fact sheets containing key issues and questions for advertisers and ad hosts.

The ACCC counts publisher ad servers among key suppliers of ad tech services.

Who gets a share: The ACCC's chart shows a simplified ad tech supply chain with a small sample of market participants

The Commission welcome submissions from all interested parties:

"The Inquiry will consider the following matters: (a) the intensity of competition in markets for the supply of, and the efficiency of markets for the supply of, ad tech services and ad agency services, with particular regard to: (i) any concentration of market power in the hands of one or more suppliers of these services, (ii) the availability of information (including pricing transparency) to advertisers, publishers and other market participants, (iii) auction and bidding processes used to supply of digital display advertising, (iv) the impact of mergers and acquisitions on those markets, (v) supplier behaviour, and (vi) how competition in these markets impacts on competition in the supply of digital display advertising services (b) the relationships between suppliers and customers in markets for ad tech services, ad agency services, and display advertising services, and (c) whether ad tech services, ad agency services, and display advertising services are being provided to the satisfaction of all market participants."

What they get: Fees charged by the ad tech supply chain, from the ACCC's issues paper