By June 1987, the portfolios "insured" by LOR and its licensees were sufficiently large that Leland was pointing out that "if the market goes down 3 percent, which, in those days, would have been a very large one-day move, we could double the volume [of trading] in the New York Stock Exchange" (Leland interview). (Although by then LOR's portfolio insurance was implemented primarily with futures, index arbitrage would transmit selling pressure from the futures to the stock market.) With sales on that scale, would informationless selling really have no effect on prices?

Donald MacKenzie, An Engine, Not a Camera, loc. 811