Hollywood Stock Exchange

The Hollywood Stock Exchange is a play-money prediction market that lets participants wager on box-office results and Academy Awards. Its record—from correctly calling all six major Oscar winners in 2000 to producing the strongest available forecast of a film’s opening-weekend box office—shows how a market can turn dispersed judgments into useful predictions without requiring substantial financial stakes.

A prediction market for Hollywood

The Hollywood Stock Exchange, commonly known as HSX, allows participants to wager on box-office returns, opening-weekend performance, and Oscar outcomes. Unlike the Iowa Electronic Markets, which uses real money, HSX uses play money. The contrast makes the exchange useful as a test of whether prediction markets need substantial financial rewards in order to draw out informed judgments.

HSX belongs to a wider family of decision markets that treat prices as a means of combining many participants’ separate views. In such a market, a forecast is not necessarily the opinion of a representative sample of the public; its potential strength lies instead in aggregating independent information and judgments. HSX’s Oscar and box-office records provide concrete tests of that proposition.

The 2000 Oscar forecasts

In March 2000, a team of twelve reporters from The Wall Street Journal sought to predict the Academy Awards by canvassing members of the Academy of Motion Pictures Arts and Sciences. The Academy objected publicly, with its president criticizing the effort to reveal the results before Oscar night, and urged its members not to speak to reporters. The Journal promised anonymity, however, and 356 members—about 6 percent of the Academy—disclosed how they had voted.

The Journal published predictions for the six major categories the Friday before the ceremony: Best Picture, Best Director, Best Actor, Best Actress, Best Supporting Actor, and Best Supporting Actress. It correctly picked five winners. HSX picked all six. The contrast is striking: a market based on play-money trades outperformed an intensive reporting effort that had obtained information directly from hundreds of voters.

HSX also performed well in a different Oscar task. In 2002, it correctly identified thirty-five of the eventual forty nominees. The result extends the exchange’s demonstrated forecasting beyond choosing winners to anticipating which contenders would make the final list.

Box-office performance and practical use

HSX’s box-office forecasts were less impressive overall than the Iowa Electronic Markets’ election forecasts, but a comparison by Harvard Business School marketing professor Anita Elberse found a particular strength: the exchange’s closing price on the night before a movie opened was the single best available forecast of its weekend box office. Its predictions therefore had practical value beyond the game. Cantor Index Holdings, HSX’s owner, began marketing the exchange’s data to Hollywood studios.

That commercial interest also shows how an aggregation mechanism can become useful to an industry even when its participants are not betting real money. HSX’s forecast was not presented as infallible; rather, its closing price compared favorably with the other Hollywood tools available for predicting an opening weekend. The market’s informational value lay in the relative reliability of its combined estimate.

Incentives without substantial money

Evidence from HSX and the Iowa Electronic Markets suggests that financial rewards can sharpen attention, helping explain why the real-money Iowa market tended to produce more accurate forecasts. But money was not the only possible incentive. Researcher David Pennock, who studied prediction markets, found that active participants in markets such as HSX could be motivated by status and reputation to invest serious time and effort, even when the wager itself was only a game.

The exchange thus illustrates a broader point about collective judgment: a market can gather dispersed information through participation, but the incentives sustaining that participation need not be exclusively financial. In HSX’s case, the play-money format coexisted with notable Oscar results and a commercially useful box-office forecast, while reputational rewards helped explain why traders took the activity seriously.