Underdog, a sports prediction market and fantasy operator, does at least one thing better than anyone else: provide accurate, near-instant injury and roster move updates on social media. There is not a close second in terms of popularity.

Appealing to gamblers, fantasy sports enthusiasts and even regular fans who crave player information as soon as possible, three different sports-specific Underdog accounts on X have amassed following counts over 200,000 in just five years, led by Underdog NBA’s 750,000 followers.

Underdog WNBA could become the fourth sports-specific account to reach 100,000 this season. That’s in addition to a main Underdog account with 341,000 followers.

Those totals tower over the X accounts of almost any of Underdog’s gaming competitors, including DraftKings, FanDuel, Fanatics and Kalshi. While most Underdog competitors supplement advertisements with generic sports memes and, in some cases, engagement bait, the majority of the posts from Underdog’s sports-specific accounts comprise up-to-the-minute player news updates.

Of course, aggregating player news on a free-to-use social media platform is not a direct revenue driver. And like other operators, Underdog sprinkles product promos into its social media output and dabbles in low-hanging jokes that risk annoying followers, such as trolling Oklahoma City Thunder guard Shai Gilgeous-Alexander so thoroughly for flopping during the NBA playoffs that it reportedly received a cease-and-desist from SGA’s representatives.

But overall, Underdog provides a service that establishes goodwill with many sports fans, some of whom turn on mobile push notifications. Underdog’s strategy, news director Jay Persson told Sportico in an interview, is to build trust with both active and potential customers.

At a key moment for Underdog—it executed layoffs in March in part to reallocate staff resources toward prediction markets—a company that raised money at a $1.23 billion pre-money valuation last year hopes its defining social media presence will help it remain near the top of the U.S. exchange betting volume rankings amid stiff competition.

Underdog recently began executing prediction market bets through Aristotle Exchange, which it acquired for an undisclosed sum earlier this year. The company declined to provide financial details on that transaction, but exchange purchases by DraftKings, Polymarket and Robinhood over the past year all cost more than $100 million when including performance incentives.

Before Aristotle Exchange’s launch, Underdog solely served as a broker for third-party exchanges, a setup with fewer upfront expenses but less product control.

“A major factor in the company’s growth has been trust with sports fans—you can buy that temporarily, but for long-term trust, you have to build it, which takes work and a genuine understanding of sports fans,” Persson said in a follow-up statement after the interview. “And the news operation follows that belief and has thrived because we’ve invested in something too rare in modern information ecosystems: being deeply scrupulous about being accurate and fast.”

Player updates as a service

Behind the scenes, Underdog staffers manage Google spreadsheets that resemble the work of accounting departments. These documents track injury reports, practice participation and personal notes for all players. When possible, Underdog pre-writes social media posts (such as for a player being ruled out for a known knee injury) that can be copied, pasted and sent out on social media at a moment’s notice.

Underdog staffers watch curated feeds of just about any account that’s ever broken player news, and they are also in touch with any coworkers on the ground at arenas or stadiums. Underdog views even a 60-second delay on sharing news as a total failure, Persson told Sportico. Thirty seconds is the baseline goal.

Accuracy is also crucial, as bettors use the information in real time to make decisions.

Much of the original Underdog crew, including Persson, came over from Fantasy Labs about five years ago. Fantasy Labs used to be the leader in player updates on what was then known as Twitter.

“While starting a content tool and information site isn’t curing cancer, it did feel good to help other people have success,” Peter Jennings, who founded Fantasy Labs before selling it as part of Better Collective’s Action Network acquisition in 2021, said on the Unabated Podcast. Jennings is an investor in Underdog.

Whereas Fantasy Labs’ web and app products were extensions of its social media presence, providing tools to build daily fantasy sports lineups and betting slips while earning revenue for referrals to gaming sites, Underdog’s product is the gaming itself.

Fantasy Labs still runs its sports-specific accounts. Without the original staffers, though, its X pages have withered with few engagements on most posts. Underdog has taken the mantle. Fantasy Labs did not immediately respond to a request for comment. Its parent company’s publicly traded stock is down about 42% since its 2021 IPO.

In recent years, Underdog has interspersed player news posts with occasional game highlights and jokes that often see high engagement rates. When possible, the accounts draw from public discourse of the day, such as a 2025 post from Underdog NBA reading, “Lauri Markkanen (tanking) ruled out Monday.”

Sometimes, updates need no embellishment to go viral. Case in point: “Gradey Dick (pelvis) ruled out for Tuesday.” Social media’s elementary school humor took it from there. (Dick is in on the jokes, once posing for a jersey swap picture with Anthony Black.)

Underdog isn’t immune from criticism over how it pushes its underlying product—now mostly prediction markets after a previous focus on daily fantasy. Some followers wish the company would decrease the number of promos interspersed among the helpful injury updates.

“We don’t care about your gambling scams we’re just here for the aggregation,” one person wrote in response to an Underdog prediction market post Saturday on X.

It’s an ongoing challenge to balance engaging content with driving customer sign-ups, Persson acknowledged, and something the team continues to think about and fine tune.

Aristotle activation

As Underdog did the media rounds last week to announce its Aristotle Exchange was being activated, CEO Jeremy Levine appeared on CNBC’s The Exchange armed with an eye-catching graphic. The image showed Underdog behind only Kalshi and Robinhood in prediction market betting volume since September 2025. Media outlets widely aggregated the stat.

Marking Underdog’s timeline “since September 2025” was a convenient framing. Polymarket’s U.S. exchange didn’t fully launch until this March; now that it is fully operational, Polymarket is seeing up to eight times as much notional volume as Underdog, which brokered bets through other exchanges before Artistotle’s activation. Polymarket chose not to be a broker while setting up its own exchange infrastructure.

Still, fourth place with a U.S. market share likely approaching 2% is a positive position for Underdog, especially considering the company’s trailing Levine’s company.

FanDuel and DraftKings are among the firms with higher valuations than Underdog that are seeing less prediction market volume than Underdog this month, when cross-counting volume as both a broker and an exchange.

Underdog is currently certifying the types of prediction market wagers it will offer through Aristotle, with 13 filings approved by the Commodity Futures Trading Commission (CFTC) to date. By this fall, the company expects to have a deep catalogue of bets to entice customers.

“As we head into NFL season,” Levine told CNBC, “it’s going to be a huge leap and a lot more we can offer to our customers.”