Market efficiency was treated as an ongoing process, not an achieved fact

Evidence

Finance theorists believed that markets were made efficient by the actions of arbitrageurs and other knowledgeable investors, so there was no contradiction in those theorists seeking to take these actions themselves. Nevertheless, that they did so shows that they did not construe market efficiency as an already-achieved fact. Rather, the achievement of efficiency was a process perhaps an endless process’ in which they could themselves sometimes take part and from which they could profit. — Donald MacKenzie, An Engine, Not a Camera, 1115

Categorization

• DEFINE: Clarifies the performativity nuance: theorists saw their own trading as helping constitute efficiency rather than just describing it — a key move in the performativity thesis.
• XREF: connects to: Market efficiency seemed sufficient for describing returns only briefly in the 1970s — Donald MacKenzie, An Engine, Not a Camera: How Financial…, 391