Efficient-market theory threatened brokers’ income by discouraging trading

Evidence

When Treynor stepped down as editor of the Financial Analysts journal, in 1981, his last editorial was pointed. The journal, he wrote, has “enemies” because “it encourages investors to distinguish between good research and bad research.” The former often led to the efficient-market conclusion that “securities are correctly priced, with nothing to be gained by buying or selling.” However, no transactions meant no income for brokers or market makers, so “a few greedy exceptions to the generally high-minded people in the securities industry consider they have a vested interest in bad research”-research that claimed to identify what were in reality non-existent opportunities for profit (Treynor 1981). The Financial Analysts journal, said Treynor, could be seen as “one small, unimportant front in a much larger war.” — Donald MacKenzie, An Engine, Not a Camera, 360

Categorization

• XREF: The material-incentives-of-ideas angle echoes the book’s own performativity thesis: the objectivity of finance theory was not neutral, it threatened specific economic interests. Connects to the discussion in earlier chapters of how CAPM and efficient-market ideas were contested by practitioners. — connects to: Efficient-market theorists held that conventional security analysis adds no net value — Donald MacKenzie, An Engine, Not a Camera: How Financial…, 351; Practitioners experienced efficient-market theory as a professional identity threat — Donald MacKenzie, An Engine, Not a Camera: How Financial…, 354