There has been an unexploited arbitrage opportunity in the Intrade Democratic VP market (&#8221-2008 Democratic VP Nominee (others upon request)&#8221-). As the attachment shows, you can sell the slate of candidates for 123.2 (just sum the bids) while you will only have to payout 100. This possibility has existed for at least three weeks, and is particularly puzzling now given that the announcement is likely to occur this week.

What is also a bit odd is that Intrade has another market (&#8221-2008 Democratic Vice-Presidential Nominee (with Field contract)&#8221-) on the same outcome which includes a catch-all field contract which does not have the same arb&#8211-again see the attachment below. It is substantially cheaper to buy the field contract in the second market than the omitted candidates (Kaine, Sebelius, Hagel, Schweitzer, Gephardt, Kerry, and others) in the first market.

Any thoughts on why this is occurring?

attachment: intradedemvp_summedbidsexceed100.pdf