The massive adoption of passive products, particularly exchange traded funds, is having a pronounced impact on the stock market, but in ways that may not be apparent to the average investor, according to Goldman Sachs.

“One unintended consequence from the relentless inflow of passive is the liquidity profiles of stocks—even those with related fundamentals—now look vastly different,” wrote Goldman analysts led by options strategist Katherine Fogertey, in a note to clients, MarketWatch reports.