Every day-trader dollar is worth five in a new theory on stocks Day traders claiming bragging rights for this year’s $9 trillion U.S. equity rebound can find some supporting evidence in the latest research.Even as retail trading has grown to represent 20% of daily volume, Wall Street has struggled to figure out how much this modest-sized contingent actually influences prices. After all, the market is teeming with algorithmic funds, long-only managers and more.But a fresh way to understand stock fluctuations via academics at Harvard University and the University of Chicago makes the effort a little easier.By weighing up the sensitivity of various players to prices, they shed light on how individual investors may have ended up calling the shots in the world’s biggest equity market.New research highlights price insensitivity of big funds and institutions.The Inelastic Markets Hypothesis. The research, titled “In Search of the Origins of Financial Fluctuations: The Inelastic Markets Hypothesis,” isn’t focused specifically on the retail-investing crowd, but the correlation is clear.Xavier Gabaix and Ralph Koijen’s theory is that institutional managers are largely insensitive to prices because their buying and selling is primarily driven by their mandates.