Until about 10 years ago, most futures trades in the United States occurred among floor
traders in the “trading pit” for each contract. Today, however, trading is overwhelmingly
Prediction Markets
If you find S&P 500 or T-bond contracts a bit dry, perhaps
you’d be interested in futures contracts with payoffs that
depend on the winner of the next presidential election, or
the severity of the next influenza season, or the host city
of the 2024 Olympics. You can now find “futures markets”
in these events and many others.
For example, both Intrade ( www.intrade.com ) and Iowa
Electronic Markets (
www.biz.uiowa.edu/iem ) maintain
presidential futures markets. In July 2011, you could have
purchased a contract that would pay off $1 in November 2012
if the Republican candidate won the presidential race but
nothing if he lost. The contract price (expressed as a percent-
age of face value) therefore may be viewed as the probability
of a Republican victory, at least according to the consensus
view of market participants at the time. If you believed in
July that the probability of a Republican victory was 55%, you
would have been prepared to pay up to $.55 for the contract.
Alternatively, if you had wished to bet against the Republi-
cans, you could have sold the contract. Similarly, you could
bet on (or against) a Democrat victory using the Democrat
contract. (When there are only two relevant parties, betting
on one is equivalent to betting against the other, but in other
elections, such as primaries where there are several viable
candidates, selling one candidate’s contract is not the same
as buying another’s.)
The accompanying figure shows the price of each con-
tract from July 2011 through Election Day 2012. The price
clearly tracks each candidate’s perceived prospects. You
can see Obama’s price rise dramatically in the days shortly
before the election as it became ever clearer that he would
win the election.
Interpreting prediction market prices as probabilities
actually requires a caveat. Because the contract payoff is
risky, the price of the contract may reflect a risk premium.
Therefore, to be precise, these probabilities are actually
risk-neutral probabilities (see Chapter 21). In practice, how-
ever, it seems unlikely that the risk premium associated
with these contracts is substantial.
WORDS FROM THE STREET
Do'stlaringiz bilan baham: