According to the members exchange, the proposed changes to fees are subject to a conflict of interest and would further cement incumbent venues monopoly over market data.
As part of the agreement, MEMX will form a new cloud-based digital asset entity to consume its exchange data and then periodically share a subset of that with Pyth.
US exchange MEMX recorded six days in July where its market share exceeded 3% while it saw a dollar volume of $9.94 billion in the week of 26 July.
Adrian Griffiths joins MEMX as head of market structure after the new US equities exchange increased its market share significantly last month.
US challenger exchange MEMX currently has 541 symbols trading as it prepares to go live in all NMS names this week.
The MEMX and MIAX equities data feeds will become active with MayStreet as both exchanges officially launch on 21 and 25 September respectively.
New exchange group launched by various major financial institutions has said it will now begin trading on 21 September.
The COVID-19 pandemic is disrupting the evolution of the US equity market structure causing current exchanges to lose trading volumes and upending plans for new ones to launch.
MEMX has added Citi as an investor as it gains FINRA approval for broker-dealer routing ahead of its launch in September.
US trading venue MEMX is set to take on incumbent exchanges Nasdaq and NYSE as it confirms September launch date.