- Intrade has institutional investors? Bwa? That term must have a different meaning in this context, but I have no idea what it would be.
- A bunch of bloggers crowed about Obama's leap up on Intrade a few days ago, but what I saw was different: the Intrade market was simply allowed to catch up with the others.
- And therefore, the lack of McCainflation created a little bubble of baseless extra confidence and perhaps contributed to the Obama camp's anxiety that its supporters are growing complacent.
- But if that's true, why are Republican hacks so eager to make the case that McCain isn't so far behind after all?
Showing posts with label intrade. Show all posts
Showing posts with label intrade. Show all posts
Friday, October 17, 2008
Intrade manipulation confirmed
Tim Jarret noticed this story before I did: the manipulation of the Intrade market to improve John McCain's standing has been confirmed. Tim has a couple of interesting insights about the situation, and I'll pop out a few bullet points of my own:
Monday, October 06, 2008
No-risk free money in the presidential betting markets
A couple of weeks ago, I wrote a couple of posts about the divergence between Intrade and fivethirtyeight.com in their estimates of the probable results of the upcoming Presidential election. In the second of those posts, I linked to Nate Silver's recognition that the betting markets themselves did not agree: Intrade consistently leans Republican relative to the Iowa Electronic Markets.
As it happens, I paid close attention to the two markets on Saturday, and I saw the prices converge, with the IEM probability of a Democratic victory steady around 71 and the Intrade probability drifting up to that level from the sixties. That evening, a hammer dropped: a huge, sudden sell order of the kind Nate had identified reinstated the Republican lean of the Intrade markets, and it has remained intact since, even growing. At this writing, the probability of a Democratic victory (which creates a slightly neater comparison than the Obama-only price) is this:
Intrade: 68.1 (ask 68.3)
IEM: 76.4 (bid 75.0)
That's spread of 8.3 points between the prices of the most current sales! (Incidentally, the Nate Silver model has the probability creeping closer to 90% now.) That spread is the kind of problem that arbitrage should be fixing, and I hope people who understand these markets better than I do can comment on why it's not. But here's how the arbitrage trade would work, and this is why I included the current ask (selling) price for Intrade and bid (buying) price for IEM as a more realistic estimate of what a trader could do right now.
The way the arbitrage trade works is that you short sell the commodity where it is priced high and buy shares where it is priced low. The principle is incredibly simple, although its application is often wickedly complicated: it's like buying a bag of peaches for eight dollars and then selling them for ten.
In this case, let's say you start by selling 100 DEM shares on IEM, where the price is higher. Buy low, sell high. (This is short selling, so you sell first and pledge to buy later; a short sell makes money if the price goes down.) At $75 each, that gives you $7500. At the same time, you buy 100 DEM shares on Intrade. at $68.30, that costs you $6830.
In a month, you're going to get the value of 100 Intrade DEM shares (the ones you bought) in exchange for the value of 100 IEM DEM shares (the ones you sold short). And this is the key: at that point, the values will necessarily be the same. Either all those shares are worth $100, or they're all worth nothing. Either the Democrats will have won, or they won't have won. The share values must converge.
So if Obama wins, you get $10000 for the 100 shares you bought on Intrade (now worth $100 each), which nets you $3170 ($10000 minus the original cost of $6830). That's balanced by your loss on the short sale of $2500 (buying back shares for $10000 that you sold for $7500). The net is $670.
And you get the same amount if McCain wins. In that case, you lose the $6830 you paid for the Obama shares, but you get to buy back your short sell for nothing, which means you keep the original $7500 you received by making the sale. The difference is again $670.
Your balance on November fifth, no matter who wins: $670.
That's a fantastic guaranteed return for a month, even if you add in the transaction costs, and even if you don't compare it with the current behavior of the equity markets.
So why on earth is this difference persisting? There seems to be a serious issue with market manipulation--as Nate suggested--or with some other kind of market inefficiency. My sense is that the problem is more with Intrade with IEM, which is important given that a lot of serious people, such as Greg Mankiw, use Intrade to represent the voice of betting markets as a whole. Something is not working as it should here.
Note: this post does not constitute investment advice. I am not a professional. If you make investments based on blog posts by English majors, well, you figure out the end of the sentence.
As it happens, I paid close attention to the two markets on Saturday, and I saw the prices converge, with the IEM probability of a Democratic victory steady around 71 and the Intrade probability drifting up to that level from the sixties. That evening, a hammer dropped: a huge, sudden sell order of the kind Nate had identified reinstated the Republican lean of the Intrade markets, and it has remained intact since, even growing. At this writing, the probability of a Democratic victory (which creates a slightly neater comparison than the Obama-only price) is this:
Intrade: 68.1 (ask 68.3)
IEM: 76.4 (bid 75.0)
That's spread of 8.3 points between the prices of the most current sales! (Incidentally, the Nate Silver model has the probability creeping closer to 90% now.) That spread is the kind of problem that arbitrage should be fixing, and I hope people who understand these markets better than I do can comment on why it's not. But here's how the arbitrage trade would work, and this is why I included the current ask (selling) price for Intrade and bid (buying) price for IEM as a more realistic estimate of what a trader could do right now.
The way the arbitrage trade works is that you short sell the commodity where it is priced high and buy shares where it is priced low. The principle is incredibly simple, although its application is often wickedly complicated: it's like buying a bag of peaches for eight dollars and then selling them for ten.
In this case, let's say you start by selling 100 DEM shares on IEM, where the price is higher. Buy low, sell high. (This is short selling, so you sell first and pledge to buy later; a short sell makes money if the price goes down.) At $75 each, that gives you $7500. At the same time, you buy 100 DEM shares on Intrade. at $68.30, that costs you $6830.
In a month, you're going to get the value of 100 Intrade DEM shares (the ones you bought) in exchange for the value of 100 IEM DEM shares (the ones you sold short). And this is the key: at that point, the values will necessarily be the same. Either all those shares are worth $100, or they're all worth nothing. Either the Democrats will have won, or they won't have won. The share values must converge.
So if Obama wins, you get $10000 for the 100 shares you bought on Intrade (now worth $100 each), which nets you $3170 ($10000 minus the original cost of $6830). That's balanced by your loss on the short sale of $2500 (buying back shares for $10000 that you sold for $7500). The net is $670.
And you get the same amount if McCain wins. In that case, you lose the $6830 you paid for the Obama shares, but you get to buy back your short sell for nothing, which means you keep the original $7500 you received by making the sale. The difference is again $670.
Your balance on November fifth, no matter who wins: $670.
That's a fantastic guaranteed return for a month, even if you add in the transaction costs, and even if you don't compare it with the current behavior of the equity markets.
So why on earth is this difference persisting? There seems to be a serious issue with market manipulation--as Nate suggested--or with some other kind of market inefficiency. My sense is that the problem is more with Intrade with IEM, which is important given that a lot of serious people, such as Greg Mankiw, use Intrade to represent the voice of betting markets as a whole. Something is not working as it should here.
Note: this post does not constitute investment advice. I am not a professional. If you make investments based on blog posts by English majors, well, you figure out the end of the sentence.
Wednesday, September 24, 2008
Obama's chances: an update
After I posted about the divergence between Intrade's and FiveThirtyEight's estimates of Barack Obama's chances of winning in November, I wrote to the FiveThirtyEight gang to see whether they had any thoughts about the matter. They didn't reply directly, but they responded to the issue with this very interesting post about the Intrade betting.
The other markets, while favoring Obama more than Intrade, still consistently rate Obama's chances as being lower than FiveThirtyEight's estimates, so my point is largely unaffected by this new information, but this new context is essential for interpreting my first post.
The other markets, while favoring Obama more than Intrade, still consistently rate Obama's chances as being lower than FiveThirtyEight's estimates, so my point is largely unaffected by this new information, but this new context is essential for interpreting my first post.
Monday, September 22, 2008
What are the current odds of an Obama victory?
Reader, I know not what to think!
Like a lot of other people, I have for a while had the sense that Nate Silver and friends at FiveThirtyEight.com and the gloriously impersonal markets at Intrade gave me my best reading of the winds of political opinion.
The two sites use radically different methods, but they attempt to answer the same kinds of questions, and for present purposes, the question is precisely the same: what are the chances that Barack Obama will win the election in November? (Naturally, I could use McCain's name throughout this post, but I find it easier to use the numbers for the current favorite.)
FiveThirtyEight is driven by Nate Silver's attempt to aggregate poll numbers and to interpret them based on the history of polling and election results. The site combines state and national polling, tweaking the model along the way and running simulations to estimate the most likely results given current conditions.
Intrade, however, uses the emergent collective wisdom of a market to answer the same question. In theory, the simplicity of the market might do as well or better than Silver at taking all information into account. For example, Silver has been trying to model the distortions of cellphone usage in this year's polls. Because the possibility of cellphone distortions is well known, a real-money market has the potential, at least, to account for their effects without relying on a controlling modeler to estimate them: in many cases, the aggregated crowd can be sharper than the market. (See the work of Robin Hanson for more on the power of markets in politics.)
In spite of these differences, the two ways of answering the questions have produced similar predictions, with small variations due in part to Silver's model deliberately reacting slowly to new developments. Until now.
As I write, FiveThirtyEight's "win percentage" for Obama has rocketed up to 74.4%, although Obama was a slight underdog shortly after the Republican convention. Intrade's bettors also made Obama a slight underdog at that point, and they too think that Obama has regained his status as the frontrunner, but only barely: there, Obama leads 51.5%-47.4%. (For reasons not worth explaining here, FiveThirtyEight's win percentages add up to 100, whereas Intrade's probabilities will be slightly lower.)
I do not see an easy explanation for such a huge divergence. Both sites attempt to look beyond a current snapshot to project the November result, and both attempt to use all the relevant public information (Silver explicitly, Intrade by means of the market).
I welcome correction on this, but I think the plain-language way to sum up the difference is this: the market is making a big bet that McCain will perform better than candidates who had similar poll results at this point in past campaigns.
The difference must rest on a claim about the present or a claim about the future. A claim about the present would involve something like the Bradley effect--the notion that polls will artificially favor Obama because voters don't want to admit they are voting against the Black candidate. Silver has written a series of posts discounting the Bradley effect in this election, however, and even a strong belief in the effect would not explain a divergence as sudden as what we've seen.
If the implicit claim is about the future, the logic might run something like this: we're seeing a close race, and the spectacle of the current Wall Street meltdown has directed the race in a direction favorable to Obama, but this is a bubble. That is, the polls we're seeing today are like post-convention polls, which involve a predictable but fleeting bump. Today's polls are a parenthetical remark, not the story itself.
Whatever explanation you favor, this is certain: the wisdom of the betting crowd sees something behind the numbers that favors McCain--not enough to make McCain the favorite, but enough to keep the race close to a coin flip. The divergence between FiveThirtyEight and Intrade has given us a window into the differences between analytical modeling and market mechanisms.
Like a lot of other people, I have for a while had the sense that Nate Silver and friends at FiveThirtyEight.com and the gloriously impersonal markets at Intrade gave me my best reading of the winds of political opinion.
The two sites use radically different methods, but they attempt to answer the same kinds of questions, and for present purposes, the question is precisely the same: what are the chances that Barack Obama will win the election in November? (Naturally, I could use McCain's name throughout this post, but I find it easier to use the numbers for the current favorite.)
FiveThirtyEight is driven by Nate Silver's attempt to aggregate poll numbers and to interpret them based on the history of polling and election results. The site combines state and national polling, tweaking the model along the way and running simulations to estimate the most likely results given current conditions.
Intrade, however, uses the emergent collective wisdom of a market to answer the same question. In theory, the simplicity of the market might do as well or better than Silver at taking all information into account. For example, Silver has been trying to model the distortions of cellphone usage in this year's polls. Because the possibility of cellphone distortions is well known, a real-money market has the potential, at least, to account for their effects without relying on a controlling modeler to estimate them: in many cases, the aggregated crowd can be sharper than the market. (See the work of Robin Hanson for more on the power of markets in politics.)
In spite of these differences, the two ways of answering the questions have produced similar predictions, with small variations due in part to Silver's model deliberately reacting slowly to new developments. Until now.
As I write, FiveThirtyEight's "win percentage" for Obama has rocketed up to 74.4%, although Obama was a slight underdog shortly after the Republican convention. Intrade's bettors also made Obama a slight underdog at that point, and they too think that Obama has regained his status as the frontrunner, but only barely: there, Obama leads 51.5%-47.4%. (For reasons not worth explaining here, FiveThirtyEight's win percentages add up to 100, whereas Intrade's probabilities will be slightly lower.)
I do not see an easy explanation for such a huge divergence. Both sites attempt to look beyond a current snapshot to project the November result, and both attempt to use all the relevant public information (Silver explicitly, Intrade by means of the market).
I welcome correction on this, but I think the plain-language way to sum up the difference is this: the market is making a big bet that McCain will perform better than candidates who had similar poll results at this point in past campaigns.
The difference must rest on a claim about the present or a claim about the future. A claim about the present would involve something like the Bradley effect--the notion that polls will artificially favor Obama because voters don't want to admit they are voting against the Black candidate. Silver has written a series of posts discounting the Bradley effect in this election, however, and even a strong belief in the effect would not explain a divergence as sudden as what we've seen.
If the implicit claim is about the future, the logic might run something like this: we're seeing a close race, and the spectacle of the current Wall Street meltdown has directed the race in a direction favorable to Obama, but this is a bubble. That is, the polls we're seeing today are like post-convention polls, which involve a predictable but fleeting bump. Today's polls are a parenthetical remark, not the story itself.
Whatever explanation you favor, this is certain: the wisdom of the betting crowd sees something behind the numbers that favors McCain--not enough to make McCain the favorite, but enough to keep the race close to a coin flip. The divergence between FiveThirtyEight and Intrade has given us a window into the differences between analytical modeling and market mechanisms.
Tuesday, February 05, 2008
Super Tuesday Post: A Brokered Convention?
As I write, during the afternoon of the Super Tuesday Democratic primaries, the identity of the Democratic nominee for the Presidency is breathtakingly uncertain: Josh Marshall points out that two of the most influential polling services have come to incompatible conclusions about voters' opinions, and the Intrade futures for the two candidates are currently trading between 49 and 51, with Clinton just above the 50% line and Obama just below.
The closeness of the race has prompted Chris Bowers, in a widely noted blog post, to say that "the most likely scenario" in the Democratic race is a brokered convention decided by superdelegates rather than primary and caucus results. Bowers presents a brokered convention as nearly inevitable barring a whopping Clinton victory in today's elections.
Given the attention the Bowers argument has received, I think it worth noting that Intrade also has a market in the probability of a brokered convention: shares on the Democratic side last traded at $11.10, implying an underlying probability of only 11.1%, with no eye-catching volatility or trends in the price.
Reader, you choose the moral of the story, as it must be one or both of the following:
1. Something in Bowers's account dramatically understates or underweights the ways in which the party can avoid a brokered convention.
2. Bowers is more or less correct, and there are heaps of money available for the taking on Intrade.
On this blog, I try not to make points that are relevant only in a given news cycle. My intent here is to illustrate the tension between the blog narrative and the market and thereby to wonder, in the new age of prediction markets for increasingly contingent and sophisticated contracts, how frequently some of us will be checking market prices to weigh the importance of a wide range of stories.
The closeness of the race has prompted Chris Bowers, in a widely noted blog post, to say that "the most likely scenario" in the Democratic race is a brokered convention decided by superdelegates rather than primary and caucus results. Bowers presents a brokered convention as nearly inevitable barring a whopping Clinton victory in today's elections.
Given the attention the Bowers argument has received, I think it worth noting that Intrade also has a market in the probability of a brokered convention: shares on the Democratic side last traded at $11.10, implying an underlying probability of only 11.1%, with no eye-catching volatility or trends in the price.
Reader, you choose the moral of the story, as it must be one or both of the following:
1. Something in Bowers's account dramatically understates or underweights the ways in which the party can avoid a brokered convention.
2. Bowers is more or less correct, and there are heaps of money available for the taking on Intrade.
On this blog, I try not to make points that are relevant only in a given news cycle. My intent here is to illustrate the tension between the blog narrative and the market and thereby to wonder, in the new age of prediction markets for increasingly contingent and sophisticated contracts, how frequently some of us will be checking market prices to weigh the importance of a wide range of stories.
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