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

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

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.

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.

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.

Insider trading is the practice of trading a company's securities based on material, nonpublic information

"Material, nonpublic" information is essentially any undisclosed information that could have a substantial impact on an investor's decision to trade a security. While the practice is strictly prohibited on the stock market, it's now being discussed regarding less-regulated but increasingly popular prediction markets.

Prediction market Kalshi's cofounders are former Wall Street traders

Kalshi's CEO Tarek Mansour ​​has described prediction markets as 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.

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.

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.

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.

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.

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."

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.

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.

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.

Some experts and investors think short selling—a strategy in which investors bet that a stock will drop in value—helps keep the market healthy.

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.

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.

Read about why bans on short selling are a controversial policy

Generally, short selling is legal, but regulations often restrict short positions when a stock has experienced a sharp price decline (more than 10% in one day). However, negative feedback loops in times of financial crisis have given short selling a bad reputation. The government has temporarily banned short selling during previous market downturns—like The Great Recession of 2008 and the early months of the COVID-19 pandemic—but experts argue whether those bans actually improved market stability or just distorted prices.

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.

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.”

Even athletes aren't immune to the sports-betting craze

While gambling scandals occasionally blew up before 2018, the widespread legalization of sports betting provided athletes with more opportunities to bet on the games they were playing.

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.

Play a game that reveals if investors with a crystal ball make better trades

The "crystal ball" game reveals how well you would do trading stocks and bonds if you could see the front page of the Wall Street Journal one day in advance.

Kalshi announced a partnership with CNN in 2025

The partnership included an integration of Kalshi's prediction markets data across CNN's network programming. For instance, certain TV segments on CNN could show a scrolling banner detailing the odds of event contracts on the exchange.

While day trading has risen in popularity in recent years, the SEC warns it is a speculative strategy that can cause big losses

A day trader is anyone who buys and sells a stock within the same trading day. They quickly move in and out of the market to try and profit. Some day traders are professionals, while others are retail investors.

Modern prediction markets started in Iowa in 1988

The University of Iowa's Iowa Electronic Markets were introduced during the 1988 US presidential election. The beginning of their origin story almost sounds like a joke: Three economists walked into a bar.

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.

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.

'Moneyball' author Michael Lewis believes sports betting is a problem for young men

The noted journalist and author of "Moneyball," "The Big Short," and "The Blind Side" has now fixed his discerning eye on the sports-betting industry. In this interview, he explains why he sees sports betting as a problem for American society, especially boys and young men, and why he believes the government needs to regulate the nascent industry more seriously.

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.

Breaking down the jargon and strategy of horse betting

Placing bets on horse racing isn't the same as a football or basketball game. You can pick a winner (win), who will come in second (place), and even third (show). And all the bets placed on a race are pooled together and divided among the winners. This Top Ten Picks video teaches the mechanics behind each bet, and shares insider tips that can lead to more informed betting choices.

Decoding sports-betting language

The world of sports gambling is filled with insider lingo: What's a "spread"? How about a "moneyline" or a "parlay"? This resource breaks down the jargon, helping you navigate the industry or, at least, giving you the keys to talk about it.

Shorting is a high-risk and expensive investment strategy that hedge funds specialize in

Most investors buy stocks with the expectation that those stocks will be worth more tomorrow than they are today. Short selling, known as “shorting,” a stock is the opposite: The investor is betting the stock will drop in value.

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.

Mental health experts caution against youth sports betting

People in their early 20s represent the fastest-growing group of sports gamblers. That fact concerns mental health professionals, who warn that early exposure to gaming primes children’s brains to seek digital rewards.

A 2024 cheating scandal cast doubt on the industry

In 2024, National Fantasy Football Championship, a fantasy league with big payouts, fired one of its employees for manipulating data. The episode cast doubt on the relatively unregulated industry, despite the league coming down hard on the nefarious worker.

Retail investors are not professionals—they invest their own money

For retail investors, the stakes may seem higher and more personal. Critics say that this dynamic means that retail investors are more susceptible to behavioral biases that could lead them to make poor decisions when it comes to buying and selling assets. For instance, fear of missing out could cause a retail investor to buy a stock that is popular but not a financially worthy investment.

A landmark hedge fund court case once reshaped high finance

Hedge fund traders tied to insider trading by probing prosecutors are relatively rare. When billionaire hedge fund legend Steve Cohen, founder of SAC Capital, pleaded guilty to trading on inside information, Wall Street trembled. The outcome of the case remains a cautionary tale for traders today.