Part of the reason this is interesting is the possibly intentional inflation of Romney's odds (from the paper) for non-monetary gain. Indeed, losing 4 million dollars:<p><i>It does appear, however, that price manipulation by a single trader who accumulated a large
directional position on Romney may have been a factor. This trader accounted for one-third of all
bets placed on Romney during our observational window, and lost almost four million dollars in
the process. This position was accumulated by placing large bids for Romney and large o ffers for
Obama that eff ectively created a firewall, preventing prices from moving in response to incoming
information. This resulted in remarkable stability in Intrade prices for several hours on Election
Day, and at other critical moments of the campaign, even as prices on Betfair were moving sharply.
On Election Day, these orders were removed just as voting ended in Colorado, the last swing state
to close its polls. The e ect was a sharp price movement and immediate convergence to the Betfair
odds. Financial gain though correlated changes in stock prices seems an unlikely motivation for
this activity, since these correlations appear to have broken down in 2012. More plausibly, this
trader could have been attempting to manipulate beliefs about the odds of victory in an attempt
to boost fundraising, campaign morale, and turnout.</i><p>And the biased vs unbiased numbers:<p><i>Manipulation aside, one of our most striking findings is that 86% of traders, accounting for 52%
of volume, never change the direction of their exposure even once. A further 25% of volume comes
from 8% of traders who are strongly biased in one direction or the other. A handful of arbitrageurs
account for another 14% of volume, leaving just 6% of accounts and 8% of volume associated with
individuals who are unbiased in the sense that they are willing to take directional positions on
either side of the market. This suggests that information fi nds its way into prices largely through
the activities of traders who are biased in one direction or another, and diff er not only with respect
to their private information but also with respect to their interpretations of public information.</i>