Kalshi controls about 75% of prediction market trading volume. Strip out combos and that number drops to about 65%. Same exchange, same week, a 10-point swing depending on which number you read.
That gap is what Sam Schwartz spends his days on. A former investment banker and ProphetX operations team member, Sam founded The PM Pulse, a daily newsletter for people who work in prediction markets, and publishes The PM Scoreboard, a weekly ranking of the leading exchanges by trading volume.
Brian Hartman sat down with Sam to talk about what the volume numbers really say, who's gaining ground behind Kalshi and Polymarket, what he learned building an exchange at ProphetX, why better prices haven't won over most bettors, and the regulatory questions he's watching most closely.
Watch and Listen to The Interview Here - Read Below
What People Get Wrong About Trading Volume
Brian: When you look at all the trading volume, what's the biggest thing people are getting wrong?
Sam: "I don't think there's any one perfect metric that tells you exactly how the rankings look or exactly how much market share each leading exchange has. You need to look at several of them to get the full picture.
"The most obvious trend lately is that combos continue to explode, especially on Kalshi, but across many exchanges that are clearly putting time and money into promoting their combo products. Most people look at volume by notional dollars traded, which is the same as total contracts matched. The problem with that metric for combos is that one user might risk $5 to win $100 while another risks $5 to win $5,000 or $10,000. The fee the exchange makes on those two trades isn't much different. But the difference in notional volume can be 100x or more.
"So when you look at total contracts or notional dollars, volumes are being artificially inflated right now. It's still an important metric, because you can't strip combos out and disregard them completely. In my latest weekly Scoreboard, Kalshi's market share is about 75% on total contracts matched. Exclude combos entirely, and it drops to about 65%. That's a pretty good gauge of where they stand and where the other exchanges come in below them. It's also interesting to look at sports only and see how the exchanges rank there."
From Investment Banking to ProphetX to The PM Pulse
Brian: Give people the intro to you. How did you stumble into prediction markets?
Sam: "I graduated from Georgetown in May 2022 and spent two years in investment banking. I had a great experience, learned a lot, worked a lot, and built strong relationships with people who've been on Wall Street for years. But I realized I didn't want to do it long term and was looking for something I was more passionate about.
"I left HSBC in the summer of 2024 and quickly stumbled into prediction markets when I learned about Kalshi leading up to the 2024 presidential election. I'd always been interested in markets, especially sports betting markets. The more I learned about Kalshi, the more I discovered ProphetX and Novig. I met people on the ProphetX team and joined their operations team in June 2025. I was there about 10 months, until this past April.
"It was an awesome experience. They have an incredibly strong team. On operations, I worked closely with product, engineering and marketing on everything that went into building and scaling a peer-to-peer exchange and fighting for market share. When I joined, there were about 35 employees. They've essentially doubled since, to 70 or more.
"I left in April intending to launch my own company in prediction markets, and I launched The PM Pulse in mid-July. The vision is to build an intelligence layer for prediction markets, with three core pillars.
"The first, where I spend the most time, is a daily newsletter that goes out Monday through Friday at 6 a.m. Eastern. The audience is the key decision makers in the industry: founders, traders, investors, lawyers, consultants, and people working at these firms. There's a crazy amount of news every day, whether it's legal and regulatory, a company announcement, a product update, a founder interview or the latest insider trading story. It can feel overwhelming to keep up. My commitment is to stay as up to speed as possible and present it in a newsletter you can read in under five minutes. Clear, concise, no fluff, with the primary source attached to each of the 10 or so developments of the day.
"The second is The PM Scoreboard. I just posted the ninth edition. It's a weekly report I publish in partnership with Aldrin Research, and the goal is for it to become the definitive source for the most accurate and comprehensive weekly report on trading volume. It starts with a ranking of the leading prediction markets by market share over the last seven and 30 days.
"The third is The PM Spotlight. I've written four so far. I interview founders in the space and write up what they're building and my takeaways from the conversation."
Why Combos Matter
Brian: Your recent Scoreboard showed a big gap between total volume and volume excluding combos. What should people take away from that?
Sam: "Partly what I said at the start: look at these rankings through a couple of different metrics. But another takeaway is something DraftKings, FanDuel and the other leading sportsbooks have proven over the last few years. Whether you use a sportsbook, a prediction market or both, most users enjoy betting parlays or trading combos, and same-game parlays seem increasingly popular too. So this will be a product pretty much every leading prediction market exchange keeps spending a lot of time on."
Brian: As DraftKings, FanDuel and other big sportsbooks move into prediction markets, do you see the sportsbooks and their prediction markets coexisting, or is this just the evolution?
Sam: "The biggest storyline people focus on every day is the looming Supreme Court ruling. It seems possible it could come in summer 2027, but there's also a chance it's pushed out to summer 2028. I think the most likely outcome is that the Court rules in favor of what the CFTC and the prediction markets are rooting for, rather than the traditional sportsbooks and state governments. That will mostly answer your question. Between now and then, I think both will continue to be strong products for consumers."
Who's Gaining Ground
Brian: When you look across exchanges, what tells you who's actually gaining ground?
Sam: "The two biggest risers over the last month or two are DraftKings and Novig. They're neck and neck. In my last seven-day snapshot, DraftKings is a little ahead of Novig in the number three spot behind Kalshi and Polymarket. Technically fourth if you split Polymarket: Kalshi first, Polymarket US second, Polymarket's DeFi platform third, DraftKings fourth. But if you combine Polymarket, the number three spot is up for grabs, and DraftKings has it at the moment. Novig has been the fastest riser over the last four weeks.
"Not far behind, you have Rothera, the joint venture between Susquehanna and Robinhood, two large players in prediction markets for more than two years now. Underdog is fighting with Crypto.com, and ProphetX is just below as well. But DraftKings and Novig have grown the most in terms of catching up to Kalshi and Polymarket over these last several weeks."
Brian: What's one recent data point that surprised you?
Sam: "It goes back to looking at the rankings multiple ways. With names like Underdog, DraftKings and FanDuel, it's hard to know exactly where they sit. Underdog owns its own DCM, Underdog Exchange, but it doesn't route 100% of the flow from the Underdog app to it. It still has agreements with Kalshi and Crypto.com, so a percentage of its flow goes to their DCMs.
"DraftKings seems to be increasingly routing flow to the DCM it owns instead of Crypto.com, which it was doing more of in the spring and summer. FanDuel still doesn't own a DCM, so it's hard to gauge exactly where FanDuel sits. I think people underestimate that. Robinhood fits there too. They've been a huge player for more than two years, and I think they still route a significant amount of flow to Kalshi. So it's hard to see the complete picture on some of these names."
Brian: With every growing name, it's harder to keep up with all the prices spread across these markets. What does that information mean for a new trader?
Sam: "For the leaders of the big trading groups, there's a lot of useful information there. What they're most interested in is the weekly Scoreboard. It helps them understand which exchanges are doing the most volume and where to budget their time. Should they trade entirely on Kalshi or Polymarket, where most of the retail flow is, or spend time on fast-growing names like DraftKings and Novig?
"What's happening on the legal and regulatory front matters a lot too, especially for bigger trading teams trying to prepare in advance. If sports event contracts are banned for good on prediction markets, that would be a major disruption for teams investing a lot of time, money and resources and hiring new traders. They're as interested in staying on top of that as anyone in the industry."
Brian: Just about everybody I talk to who's dabbling in prediction markets got in through sports. My wife is the exception. Reality TV got her in.
Sam: "Sports continues to make up something like 85% to 90% of trading volume across all these exchanges combined. It's the clear dominant category."
If you trade across several of these exchanges, our sports page puts the best available price for each game in one place.
What Building an Exchange at ProphetX Taught Him
Brian: What did working at ProphetX teach you that people outside the industry might miss?
Sam: "How difficult and time-consuming it is to build and optimize one of these exchanges. A lot of what the ProphetX team focused on when I joined in summer 2025 was building relationships with market makers and liquidity providers, onboarding and integrating them, and encouraging them to provide liquidity across pro sports, college sports, pregame, live, props and futures. There are thousands, if not tens of thousands, of markets on these exchanges. Liquidity is key to the health of the exchange and the experience for the user, and it takes a team effort.
"When I joined, we were also working toward launching the RFQ combo product that ProphetX and many other exchanges now offer, and a ton of work goes into that too. Offering new sports, deeper player props, deeper futures or alternate lines takes a lot of product and engineering work.
"I think that was validated by how long it's taken the big players. Polymarket was talking about launching Polymarket US about a year ago. FanDuel and DraftKings made strides toward launching their own prediction markets around then too. It's taken every bit of the last year for a lot of these big players to catch up to Kalshi, and really to ProphetX and Novig, which had been building the underlying peer-to-peer infrastructure for a couple of years. People underestimate how long it takes to build the matching engine, the order book and everything else that goes with it."
Why Better Prices Haven't Won Over Bettors
Brian: What's something that's changed your mind as you've covered this space?
Sam: "Joining ProphetX was eye-opening. In the years before that, I was pretty much only betting on sports through DraftKings, FanDuel and the other traditional sportsbooks. At ProphetX, on a roughly 50/50 trade, the norm was risking something like $102 to win $100 instead of $110 to win $100. The more I thought about it, the more I was convinced this had to be the future. Who would ever keep risking $110 to win $100 instead of $102? You get better pricing on just about every bet on a low-fee platform like ProphetX or Novig.
"The biggest realization I've had is that most users of prediction markets and sportsbooks don't behave that way. DraftKings and FanDuel have shown it for years as the two clear sportsbook leaders. And Kalshi is showing it now. Whether their share is 65% or 75% depending on how you look at it, they're the number one player by an enormous margin, they keep growing every week and month, and they seem to break volume records nearly every weekend. Yet the pricing on Kalshi's main markets, moneylines, full-game spreads and totals, is pretty much in line with a sportsbook like DraftKings or FanDuel. I collected a lot of data on this and presented it in the ninth Scoreboard. You get marginally better pregame pricing on the main markets on Kalshi or Polymarket compared to a sportsbook, but it's close.
"Another data point: a year ago Polymarket had very low or zero fees in many markets, and over the last couple of months they've raised fees to be more in line with Kalshi. So on both sides, the two leaders with the most customers, DraftKings and FanDuel on the sportsbook side and Kalshi and Polymarket on the prediction market side, have higher fees than ProphetX and Novig. Most consumers are pretty price insensitive.
"That said, I probably think this more than most people: I believe users will start to value a better price more in the future than they have in the past. We'll have to wait and see how that plays out."
Brian: Why do you think that is? Why are people taking the worse price at DraftKings and FanDuel, instead of shopping across books, or going to prediction markets for better lines?
Sam: "Most people are comfortable doing what they've always done. They have their DraftKings or FanDuel app, or I guess their Kalshi app, and they don't see the need to switch. And DraftKings, FanDuel and many other platforms do a really good job with promotions: deposit bonuses, profit boosts, injury refunds. Those have all proven to be great ways to retain customers and keep them happy. A lot of factors are at play, but I think that covers most of it."
Better pricing still adds up over a season of bets. Before you open new exchange accounts, check the current sign-up offers.
Sam's Advice for New Traders
Brian: What does someone new to prediction markets need to understand before they jump in?
Sam: "They should probably consume as much PredictQ content as they can. You guys are doing an awesome job, and I really enjoy it.
"There's a lot of bad information and content out there. Jack Andrews at Unabated has been doing a great job with educational content for a long time. So have Rob Pizzola and his team at The Hammer, and Alex Monahan, the founder of OddsJam, spends a lot of time on education. When I started using X as a source of information, I tried hard to find the best content creators and consume their work, as opposed to people in the media casually talking about sports betting, or the touts selling picks online behind anonymous profiles. My number one piece of advice is to seek out the people doing a great job on the educational side."
Brian: Fight the algorithm a little bit. Don't just go to all the mainstream pages.
Sam: "Exactly."
New to all of this? Our Prediction Markets 101 covers the basics in plain language.
The Developments Sam Is Watching
Brian: What's one development you're watching closely right now?
Sam: "All of it, honestly. The Supreme Court situation is definitely at the top of the list. I also enjoy digging into the trading volumes daily to see what's driving growth or decline for these platforms.
"There are a couple of interesting situations with the CFTC right now, where it's taking feedback on how affiliated market makers should be structured going forward. That's someone like Kalshi's internal trading team, Kalshi Trading, or Manhattan Athletic Group, which was previously Novig's internal trading team, or Susquehanna, which is an owner of Rothera and also a large market maker. There's a lot of important conversation about how these affiliated market makers will fit into the ecosystem going forward."
Brian: What do you trade yourself?
Sam: "The NFL has always been my biggest focus. Number two is probably tennis, but that's on pause now that the four Grand Slams are done for 2026, and I don't spend as much time on the lower-level tournaments. I've been spending some time on market making, and I also trade college basketball and the NBA. But it's primarily the NFL, and I'm really enjoying getting back into the swing of the season."
Where to Find Sam
Brian: Where can people find you, The PM Pulse and the Scoreboard?
Sam: "My main site is thepmpulse.com, where you can find everything related to The PM Pulse. It's free to subscribe, and all the content is free. I also spend a lot of time on X at @samschwartz71."
Want to talk through combos, exchange pricing or where the volume is moving? Jump into the PredictQ Discord.
This article is an adapted interview based on a real conversation about how one analyst tracks the prediction market industry. It is not an exact transcript, a directional prediction, a trade recommendation, or investment advice. Market share figures, rankings and other figures discussed were stated by the guest at the time of recording (October 14, 2026), are point-in-time, and may change. PredictQ is a marketing partner of Kalshi and Polymarket and may receive compensation for referrals.