Of course the exchange might not want to publish even overall numbers, as that would give less “cover” to their biggest customers.

Intrade should publish open interest data, which would make what happened at 33.3 much more clear. What is somewhat clear is that our buyer has purchased over 4000 contracts near 40 within the past few days. Given the action at 33.3, his position is conceivably over 15000 contracts. In any case, if there is any negative news on Giuliani, the trader will not be able to exit his position in a timely fashion, at reasonable prices. He is simply too big for the market as it stands. This leads one to think that he is in it for the long haul, willing to risk most of his maximum loss, and much of it to liquidity. And yet he is still buying, with an additional 7000 contracts currently near the bid.

Perhaps he actually knows something and the market is functioning well, reflecting his information. But even if, say, Romney is about to drop out, the buying is very aggressive and he won’t be able to effectively liquidate in any bounce. Perhaps it is an actual hedger? In both these cases, however, why make the pretense of the market-maker spiel? Also, if the trader is someone close to a politician, it is a risk in itself for them to be trading conspicuously on a de facto illegal offshore exchange during US hours.

Selling the Giuliani / McCain spread seems like a good trade, but if you look at the McCain market, less than 150 contracts are offered below 40, which underscores how large our Giuliani trader is.