In this article talking about market makers within the options market:
Options on key indexes, exchange-traded funds and high-volume stocks dominate trading. Meanwhile, there is less activity in the rest of the listed U.S. options world.
The stresses prompted at least six prominent options market makers to exit from the business since 2012. Market makers are firms willing to both buy and sell using automated programs.
A lightning-rod issue in options trading has been auctions designed to provide the best prices for investors by redirecting some retail orders into a separate auction process. They have curtailed market makers’ ability to interact with retail orders, giving them less incentive to provide quotes, traders say.