The Rise of Prediction Markets

The idea of prediction markets may have begum as a small research tool in Iowa in the 1980s with trading volumes measured in the thousands of dollars. After a few decades, monthly dollar volume for private prediction markets had reached millions of dollars. Recently, prediction markets have hit the big time. The WSJ reports that Polymarket and Kalshi now do about $3-4 billion of volume in a month. To be sure, this is still three orders of magnitude smaller than the volume of the NYSE or NASDAQ of $2-3 trillion. But this impressive growth indicates broad acceptance. 

The idea is simple. If a contract will pay $1 if an event occurs and I think the event will occur with probability P, my expected value of owning the contract is $1 x P or $P. If it is currently trading for less (more) than $P, I can expect to make money buying (selling) the contract. With enough  potential traders, the price being quoted is "the market's" best estimate of the probability of the event. Traders' profit motives drive the price to the "the market's" expectation.

Non-traders, perhaps ignorant of how new information will affect the probability, need only look at how much the price has changed to infer what more knowledgeable individuals think of the information. Prediction markets harness "the wisdom of the crowd." The growth of these markets is an indicator of how valuable this information can be.

Economist: the world is more equal than you think.

 Economist:  

[in 2000], the rich spent about 40 times more than the poor; today the figure is closer to 18. ...

But in many countries where populist politicians lament that poor folk have been left behind, consumption gaps have more recently narrowed—suggesting that lower-income households are catching up. This has happened quickly in Spain and Greece, and also in Britain and France. Inequality can be gauged in different ways. On consumption, it’s mostly good news.■

 

If we tax the rich, ...

...they will leave, work less, and there are not enough of them to raise much money. 

The Economist: 

The “Robin Hood” state, which takes from the rich to give to the poor, has obvious appeal. Governments across the developed world are strapped for cash. Budgets are burdened by legacy debts, ageing populations and the need to spend more on defence. 

INSTEAD ...

The limited revenue-raising power of the rich is why European governments have to fund their big spending with broad-based levies, such as taxes on consumption. By contrast, America, with its low overall tax burden, can get by with one of the world’s most progressive tax systems.

Broad-based taxes do not only raise much more money. They are also politically healthier. A society where the many pay tax and benefit from spending is stronger than one where the few have to pay for the many.

BOTTOM LINE: lower rates on a broader base typically produce more tax revenue ... than high rates on a narrow base. ...

HOWEVER, if progress on artificial intelligence concentrates incomes at the top, as almost everyone in Silicon Valley expects, then the tax system will require fresh thinking:  ... we may have to figure out how to redistribute wealth without destroying too much of it.  

It Has Become Cheaper to Lose Weight

Finding out that GLP-1 drugs can help reduce weight has been life changing for many and could stem the social costs of being overweight. Recently, prices have fallen dramatically. I asked ChatGPT to for some summary data for Wegovy & Zepbound which I plot below. 

Competition matters. Initially, Wegovy was the effective monopolist selling at a list price of $1,349. In November 2023. Zepbound was approved and entered at just over $1,000 but dropped its price to ~$500 in Spring 2024. Wegovy may have sold at discount by Fall 2024, but it's direct-to-consumer price did not fall to ~$500 until Jan 2025.

It will be interesting to see if similar adjustments occur over the next few years as at least three new entrants are expected..

 

Country Music Stars and two imposters

 Testifying on Media consolidation 2006.  

Back Row:  Cowboy Troy, Big & Rich, Harold Bradley, Rick Carnes, Econ Prof Luke Froeb, Dobie Gray, Sharon Kay

Front row:  Naomi Judd, George Jones, Jenny Toomey, Porter Wagoner, Bud Walters, Craig Wiseman, Law Prof Christopher Yoo 

What drives the male-female wage gap?

Economist:  Motherhood 

• Researchers took women undergoing in vitro fertilisation (IVF)—who clearly wanted children—and examined the difference in long-term wages between those who fell pregnant and those who did not. At first the mothers earned much less, but this gap shrank over time. 

• Now this approach of exploiting natural variation in fertility has been used in a new study, by Camille Landais of the London School of Economics and others. 

• It looks at women with Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome, a rare condition in which a girl is born without a uterus but otherwise develops normally. These women know early in life that they will not bear children, ...

• Such early knowledge seems to make a big difference. ... Their wage trajectory is almost identical to that of their male peers. 

• In other words, remove both motherhood and any decisions women might make while anticipating it, and the wage gap seems to vanish. 

Differences-in-Differences: Handwashing and Waterborne Transmission of Cholera

 From: Carlos Chavez, On Causality

Difference-in-differences has undergone a methodological renaissance. The method’s intellectual roots reach back further than most economists realize - to the 1840s and 1850s.

• In 1847, Ignaz Semmelweis used comparative clinic analysis to show that handwashing prevented childbed fever, comparing mortality between Vienna’s physician-staffed ward (where medical students performed autopsies) and its midwife-staffed ward, then tracking outcomes after implementing chlorine disinfection.

•  John Snow’s 1854 investigation of cholera in London is credited as the first recorded application of difference-in-differences proper. Snow compared mortality rates across households served by two water companies: the Lambeth Company, which had moved its intake upstream of the city’s sewage outflow in 1852, and the Southwark & Vauxhall Company, which continued drawing contaminated water. By comparing changes in cholera deaths before and after Lambeth’s relocation - while Southwark & Vauxhall served as the control - Snow produced a cleaner diff-in-diff design, with parallel pre-treatment trends giving way to dramatic divergence. His “Grand Experiment” found 315 deaths per 10,000 households among Southwark & Vauxhall customers versus only 37 per 10,000 among Lambeth customers, providing powerful evidence for the waterborne transmission of cholera decades before germ theory was established.

Where is it cheaper to rent vs. buy?

.

The Economist:  In long-run equilibrium, buyers should be indifferent between renting and buying. If buying were cheaper, then some renters would buy, which would drive down rents and drive up prices, until consumers became indifferent between the two options.  

One of the signs of a housing bubble is when it is cheaper to rent.  

Calif. "Jock Tax" takes Half of Superbowl Players' Cut

Superbowl players earn $178,000 each if they win and $108,000 if they lose. But California taxes athletes based on the number of "Duty Days" spent in the state, eight for the Superbowl. Jeffrey Degner, of the American Institute for Economic Research (AIER),crunched the numbers to calculate that the average player will leave California with much less.

"What that means here is that the winning team, their take-home pay will be approximately $86,000. If you're on the losing side, the take-home would be about $49,800," Degner said. 

Because the tax is based on you salary, winning Seahawks QB Sam Darnold will actually pay more in taxes than his Superbowl compensation. I suspect the NFL Players Association will want to revisit holding future Superbowls in California.

Economies of scope between SpaceX and xAI

Link:

The merging of what is arguably Musk’s most successful company, SpaceX, with the more speculative xAI venture is a risk. Founded in 2023, xAI’s main products are the generative AI chatbot Grok and the social media site X, formerly known as Twitter. The company aims to compete with OpenAI and other artificial intelligence firms.

...

With this merger, he plans to use SpaceX’s deep expertise in rapid launch and satellite manufacturing and management to deploy a constellation of up to 1 million orbital data centers. This will provide the backbone of computing power needed to support xAI’s operations.

HT: MarginalRevolution