[dchftcs]

>Are these "market makers" working behind the scenes to facilitate the operation of those retail facing companies

Yes. Brokers like Fidelity have no idea how to price things, and even when they do, they don't know know how to manage the risk. Marker makers quote at the tightest prices they can offer and you trade against them, through your broker, on or off-exchange.

Market makers are often much more efficient and automated than brokers, but have similar or lower margins as a business and take a lot more risk. There's a misguided anger directed to electronic market makers, but it's in fact brokers that've been ripping you off all along.