@Oliver asked a great question about the regulatory risks associated with Graphcast in the Core Dev Call (The Graph | Core Devs Call #15 - September 1st 2022 - YouTube), and also specifically mentioned Price Fixing as a risk.
On regulatory risk:
Each Indexer is subject to the regulations and legal requirements of the jurisdiction in which they operate. Graphcast is merely a messaging technology and will not prevent participants from using it in a way that may expose them to regulatory risk. Doing so would be against the spirit of decentralisation and permissionless participation, so it’s really up to each Indexer to ensure that they are following the laws applicable to them.
On Price Fixing with Graphcast:
Graphcast will not prevent price coordination from happening via gossip. If sufficiently motivated parties want to coordinate on price, there are a million ways to do so, and if it were to happen via gossip, at least that is fully transparent to observers, rather than via “dark channels”.
On Price Fixing more generally:
Pricing should generally resolve to some natural equilibrium, driven by the underlying factors of supply and demand.
Price fixing is most problematic in markets that are not permissionless or otherwise have high costs and/or friction associated with entering the market. Rigid bases of supply are more susceptible to capture by a price fixing cabal.
For example, in markets where there are regulatory barriers to entry (e.g. pharmaceuticals), price fixing is much easier to execute, because new market entrants are much less able to take advantage of the pricing opportunity created by price fixing.
In permissionless markets, new entrants are always able to enter the market and compete with existing suppliers. This makes it much more difficult for price fixing to take hold of the market. Instead, as price fixers raise their prices, they create strong incentives for revenue-motivated indexers to swoop in and serve demand at a lower price, making mid-market price more reflective of the natural market equilibrium.