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 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 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.

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

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

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.

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.

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.

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.

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.

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.

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.

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.

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 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.

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.

'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.

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.

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.

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 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.

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.

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.

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.

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.

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.

Hear what Michael Burry thinks about the possibility of an AI bubble

Since his success shorting subprime mortgage-backed securities in 2008, Burry's positions have often become influential, sparking conversations on platforms like X. In 2025, Burry drew attention for betting against Nvidia and Palantir for being overvalued companies.

Hear why one short seller thinks short selling is now more important than ever.

Retail investors are getting burned by long/short strategies

In the US, many retail investors lack the SEC-mandated status (a high enough net worth, income, and other factors) to directly invest in hedge funds. The regulator considers hedge funds too risky for the masses. Hedge fund-like strategies have emerged as a workaround, despite potential pitfalls.

Ethereum Founder Vitalik Buterin was surprised by the emergence of NFTs

Scams have pervaded the NFT space and made critics question their legitimacy, but proponents believe their use cases could one day extend to real estate and credit scores.

'Daily fantasy' is a high-stakes subset of fantasy sports

The form, pioneered by platforms like FanDuel and DraftKings, uses anonymous daily leagues and large payouts, looks more like typical betting than the season-long, community-minded setup of more traditional fantasy.

Smart pricing algorithms can unintentionally work together to raise prices

Researchers have found that, through trial and error, algorithms designed to adjust prices based on market data can learn to mimic price-fixing tactics, even without explicit programming to do so. Over time, they "learn" that it is more profitable to avoid price wars and keep prices high when competitors lower prices.

Using cryptocurrency to turn traditional financial arrangements on their head

Cryptocurrency is poised to drastically change everything in the financial world, including financial arrangements. Decentralized finance makes it easier for virtually anyone to take advantage of financial markets without the need for a bank. However, there are new risks involved as well. Professor of Legal Studies and Business Ethics Kevin Werbach, an expert on Bitcoin and blockchains discusses it all in detail in The Conversation.

In 2012, Bill Ackman's hedge fund, Pershing Square, took a $1B short position against supplement company Herbalife after discovering that 82% of the company's distributors never made a profit, calling it a true pyramid scheme.

'The stock market' can be loosely defined as a set of exchanges and other places where shares of public companies are bought and sold.

Social media platforms benefit not just from ensuring they have satisfied users, but also from the personal data they scoop up and can then sell to online advertisers.