Modern prediction markets—the platforms where people can trade bets that pay out depending on certain event outcomes—started in Iowa in 1988.

Prediction markets and sports betting are not forms of investing, despite how some fans portray them.

The 2024 US presidential election was a breakthrough moment for prediction markets

Founded in 2018 by MIT graduates, Kalshi won a federal appeals court ruling in October 2024 that allowed it to offer election contracts in the US. When prediction markets predicted President Donald Trump's win (more accurately than most polls), prediction markets were thrust into the public eye.

A prediction market was more accurate than most polls about the 2024 US presidential election

The idea that the median estimate of a group can be more accurate than individual expert estimates is called the "wisdom of the crowd," and dates back to the early 1900s. This theory can help explain the perceived value of prediction markets when it comes to polling and more.

Prediction market Kalshi's CEO Tarek Mansour ​​has said that prediction markets are similar to the stock market—except instead of buying and selling shares of companies, users buy and sell "yes" or "no" on whether an event is going to happen or not.

Prediction markets—the platforms where users can trade bets that pay out depending on certain event outcomes—have faced questions about insider trading.

The prices on prediction markets reflect how the collective forecasts future outcomes

On prediction markets, bettors bid up or down the price of contracts based on what they expect an event's outcome to be. Bettors bid up prices when they think an event is more likely to occur than the current contract price shows, so they buy the contracts, pushing the price higher. They bid down prices by selling these contracts when they believe an event is less likely to occur, driving the price down due to supply and demand.

Prediction markets help people bet on almost anything—which can be controversial

Critics point to incidents such as traders placing bets on the Venezuelan President Nicolás Maduro's capture and the two people in Israel who were charged on suspicion of using classified information to place bets about military actions.

Prediction markets convinced regulators they're not gambling, but exchanging commodity futures contracts

Kalshi built a legal case that argues its yes/no bets on real-world events are futures contracts, and the relevant regulator—the Commodity Futures Trading Commission—agreed in 2020. Many states are now suing major prediction markets, arguing this legal case is faulty and obscures the true substance of the business: gambling.

How prediction markets differ from sportsbooks matters for regulation

There are a number of differences and similarities between sportsbooks and prediction markets, despite both allowing people to bet on outcomes for sports-related events. For instance, prediction markets typically earn revenue through transaction fees rather than taking directional exposure to outcomes.

Some experts equate prediction markets to the new crack cocaine of gambling addiction

An addiction psychiatrist at UCLA says betting apps are far more potent than traditional gambling, citing a 19-year-old patient who lost $180,000 and hadn't left campus in a year, cycling through sports bets, crypto, meme stocks, and prediction markets on his phone. This interview explores the extreme edge of the nascent industry.

Donald Trump's Truth Social social media platform is launching a prediction market

Named "Truth Predict," the cryptocurrency-based prediction market will allow users of the Truth Social social media platform to place crypto bets on the outcome of certain events (think: sports games, the economy, and political races). Truth Social is primarily owned by President Donald Trump and his family.

Kalshi is the first regulated prediction market in the US

Two migrant MIT students, Luana Lara Lopes and Tarek Mansour, shared an interest in hedging against uncertainty—from election outcomes to the Oscar awards. They fought hard for regulatory approval and their company now has a valuation in the billions. The platform has brought prediction markets into the mainstream.

Contract prices on prediction markets are generally interpreted as implied probabilities

For example, if a contract trading is at $0.65, that could be read as the market assigning a 65% probability to that event occurring. The most common format for prediction markets is winner-take-all: The contract settles at $1 if the event occurs, or $0 if it doesn't.

Use a prediction market profit or loss calculator

In order to calculate how much someone would make from a specific trade on a prediction market, this calculator asks for the purchase price of a given "yes" or "no" prediction, the number of contracts the trader plans to purchase, and more.

Experts suggest the industry could be a $45B business

Sports betting used to primarily consist of who would win and the points spread, but the rise of online betting apps has fueled a substantial increase in parlay bets. "Existing markets are still growing at a rapid clip," said Noah Naparst, who evaluates sports-betting companies for Goldman Sachs. "So we’re not mature yet, but we’re not in the early wildcat days of the market anymore, either.”

Vitalik Buterin’s current thoughts on Ethereum

Vitalik Buterin isn’t just the founder of Ethereum—he’s also a blogger. In this blog post from late last year, Buterin discusses some of his favorite applications built on Ethereum: prediction markets like Polymarket, where users can bet crypto on the outcome of events like elections. Buterin argues that prediction markets also act as news sites for non-bettors, opening the floodgates for many different kinds of info-based apps on Ethereum. Read the post here.

A timeline of sports-betting scandals

This timeline examines memorable moments from three decades of sports-betting history. It breaks down key political moments, as well as some historical moments such as when the internet pushed underground bookmaking online. There are also multiple descriptions of betting scandals from 1989 on.

Sports betting, explained

Since a 2018 Supreme Court decision overturned the Bradley Act, which spurred a state-by-state legalization of online gambling, sports betting has become a rapidly growing multibillion-dollar industry.

Americans spent nearly $150B in sports-related bets in 2024

These bets ranged from who would win the World Series to what color clothes famous celebrities would wear to the Super Bowl. Experts believe the industry will continue to grow.

The CEOs of the two top prediction markets have a fierce rivalry

Kalshi CEO Tarek Mansour and Polymarket CEO Shayne Coplan are both billionaire CEOs of the top two prediction markets—but they don't exactly get along. For instance, Mansour reportedly does not say the word "Polymarket" out loud, referring to it as the "non-American, unregulated platform."

The worst election polling fails in US history

Presidential pollsters in the US have had some embarrassing failures. Here’s a catalog of those miscalls, from the scholar who literally wrote the book on them.

How George Gallup changed political polling forever

Straw polls had been used in the 19th century, but it wasn't until George Gallup's use of random sampling in 1936 that the art became a science.

Prediction market Polymarket's CEO dropped out of New York University

Polymarket CEO Shayne Coplan started building Polymarket when he was 21. Polymarket has been backed by billionaire investors such as Peter Thiel and Vitalik Buterin.

Sports leagues have attempted to prevent athletes from betting

As pro and collegiate sports embrace betting (and the revenue that comes with it), each league works diligently to ensure the integrity of the games by hiring private firms to analyze irregular bets. These companies have flagged bets that led to the firing of Alabama’s baseball coach, the suspension of multiple athletes at Iowa and Iowa State, and, most recently, a lifetime ban on former Toronto Raptors forward Jontay Porter by the NBA in April 2024.

How America became a nation of gamblers

For thousands of years, humans have liked to gamble. What started as dice games and betting on chariot races became a way for states to generate revenue here in America. This article explores how states have been using gambling to pay for infrastructure and capital projects–and the cost it’s had on the citizens.

Dow Theory laid the groundwork for modern market analysis

Developed by Charles Dow in the late 19th century, Dow Theory argued that markets move in trends. Its principles—confirmation, trends and volume—still influence technical analysis today.

Explore a comprehensive archive of US presidential election data

This University of California, Santa Barbara archive compiles presidential election data from 1789 to the present, including popular vote totals, turnout figures, and contextual resources that explain how the electoral process and political landscape have evolved.

Prediction markets have their own lingo that's an amalgamation of Gen Z and Gen Alpha slang

For instance, if you've been out-maneuvered by another trader, you've been "mogged." A "rulescuck" is someone who is a stickler for betting market rules and may try to win on a technicality.

Exciting US primary debate moments from history

Presidential debates in the US are highly-touted events viewed as the capstone of a campaign, but their impact on the overall polling is often undetectable. Nonetheless, the televised events can be really entertaining as candidates sweat under the pressure of a live mass audience, and most morning after news round-ups contain some of the event's notable—or cringey—moments. Here's a quick, three-minute video of highlights of some of the more fascinating moments from US primaries.

'The Simpsons' has a knack for inadvertently predicting the future

Some have noted that "The Simpsons" has accurately anticipated a number of events years before they happened, including the election of President Donald Trump, Disney buying 21st Century Fox, and Siegfried and Roy's tiger attack. This list breaks down some of the show's most uncanny inadvertent predictions.

The FBI once raided Polymarket CEO Shayne Coplan's home

In 2024, after Polymarket markets favored what turned out to be the winning outcome of the US presidential election, agents raided Coplan's New York City apartment. Coplan, who was only 26 years old at the time, was home during the raid and turned over his devices to authorities.

Electronic trading transformed investing, ushering in a new era for retail investors in which average Americans could research stocks online and then use early platforms like StreetSmart and E-Trade to conduct their transactions

In the early 1990s, stock brokerages knew that online trading would be a great equalizer, creating opportunities for more individuals to buy and sell stocks.

Some novel ideas to improve presidential debates

The first televised presidential debates of 1960 were seemingly so consequential, candidates opted not to participate in one for 16 years. In the last 60 years, debate format has changed frequently as the political parties and news outlets vie for rules to either protect candidates or increase TV ratings. In this brief video, one expert suggests five interesting innovations to the debate format to make them more informative for the average US voter.

Legal gambling on Super Bowl 60 is expected to reach $1.76B

Legal Super Bowl wagering has grown sharply over the past decade as US states legalized sports betting. In 2018, sports betting was only legal in Nevada and accounted for $158.5M.

Frictionless online gambling platforms accelerate compulsive behavior

As of late 2025, as much as 95% of bets are placed online, where "always on" betting and a variety of formats, such as prop bets and parlays, encourage users to keep participating. Experts warn that the normalization of gambling through advertisements also reduces the perceived danger of addictive gambling.

A stock market timeline

The stock market has come a long way since the 1600s, when the first version of a stock exchange was created in Amsterdam. Mile markers along the way include everything from the Dow Jones Industrial Average's creation in 1896 to the stock market woes during the COVID-19 pandemic in 2020.

How political campaigns use your data

What do campaigns know about US voters, and how do they use that information to shape their strategies during elections? US political campaigns base their strategies and tactics on data collected from more than 200 million voting-age Americans. This visualization by Reuters breaks down how data firms create national databases of voter files, collecting information from a variety of sources to create detailed voter profiles and how political campaigns use that data.

Sports media have also embraced sports betting

For decades, ESPN kept its distance between reporting on games and talking about gambling lines. Sports teams refused to have franchises in Las Vegas, fearing it would harm the sport. But since 2018, that has changed. ESPN’s personalities regularly pick games, and the company has also launched its own betting app.