Asset managers have pushed back hard, describing this research as baseless and incoherent. “The economics literature purporting to link index funds and higher prices is based on fragile evidence and fundamental misconceptions,” one BlackRock white paper on the subject argues. “It does not provide a plausible causal explanation of how common ownership can lead to higher prices.”Correlation doesn't prove causation, but this sounds very much like temporizing from people who find the trolley's current track especially rewarding. The incentives are too high to presume good faith by interested parties.