Caitlin Ostroff
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Following money for @WSJ using words, numbers and code. Co-founder: @jourmentors. Tips: github.com/ceostroff/contact. ∑: @TheAlligator, @MiamiHerald
Articles by Caitlin Ostroff
FIFA提携の予測市場、出来高のほぼ全てが循環取引
This copy is for your personal, non-commercial use only. Distribution and use of this material are governed by our Subscriber Agreement and by copyright law. For non-personal use or to order multiple copies, please contact Dow Jones Reprints at 1-800-843-0008 or visit www.djreprints.com. https://jp.wsj.com/articles/nearly-all-volume-on-fifa-linked-prediction-market-is-circular-trading-9d8cc314
Nearly all volume on FIFA-linked prediction market is circular trading
ADI Predictstreet, a newcomer to prediction markets, made a high-profile debut during World Cup broadcasts after paying FIFA more than $150 million to become the global soccer organization's official partner. Since late August, nearly every transaction on the platform has been made by a small network of linked accounts, according to an analysis of public data, suggesting that most of its trading volume is inauthentic.
Nearly All Volume on FIFA-Linked Prediction Market Is Circular Trading
ADI Predictstreet, backed by Abu Dhabi’s royal family, paid close to $150 million for advertising rights during the World Cup ADI Predictstreet, a newcomer to prediction markets, made a high-profile debut during World Cup broadcasts after paying FIFA more than $150 million to become the global soccer organization’s official partner.
Mamdani’s Pied-à-Terre Tax Hits Wealthy Out-of-Towners With a Double Whammy
New York second-home owners, including Trump envoy Steve Witkoff, face scrutiny of abatement intended for local residents Trump administration special envoy Steve Witkoff and several other wealthy property owners are getting an expensive surprise, courtesy of Mayor Zohran Mamdani’s new pied-à-terre tax.
Mamdani's pied-à-terre tax hits wealthy out-of-towners with a double whammy
Trump administration special envoy Steve Witkoff and several other wealthy property owners are getting an expensive surprise, courtesy of Mayor Zohran Mamdani's new pied-à-terre tax.
Mamdani’s Pied-à-Terre Tax Hits Wealthy Out-of-Towners With a Double Whammy
Crime 1 hour ago 'They're stealing from the poor': A major source of SNAP fraud robs recipients of millions NPR - Juliana Kim • 1h As Jayeleauna Lewis listened to an automated voice system describe the unauthorized charges on her food assistance card, a pit formed in her stomach. She pictured her 3-year-old daughter and their empty fridge back home.
How Polymarket’s ‘Growth at All Costs’ Strategy Opened the Door to Fraud
A Wall Street Journal investigation found repeated compliance failures, fraud attacks and software glitches inside Polymarket, the highflying prediction market company. That included a major fraud attack in February in which thieves tried to steal at least $10 million by linking stolen credit cards to Polymarket US accounts. Copyright ©2026 Dow Jones & Company, Inc. All Rights Reserved. 87990cbe856818d5eddac44c7b1cdeb8
米予測市場カルシでほぼ同規模の取引相次ぐ、当局が調査
8月以降、約5500ドルという同一の注文規模の高速取引がカルシの特定市場で約100万件発生 米予測市場運営大手カルシのトレーダーらは8月以降、特定の市場で約100万件の取引をほぼ同規模で行っている。これは異例の取引活動であり、連邦規制当局やトレーダーの注目を集めている。 ウォール・ストリート・ジャーナル（WSJ）が公開取引データを分析したところ、暗号資産（仮想通貨）イーサの価格を予測する市場でここ数週間、約5500ドル（約86万6000円）という同一の注文規模に集中した高速取引が、取引全体の3分の1超を占めていたことが分かった。なお、カルシの公開データではトレーダーらの身元は明かされていない。 Copyright ©2026 Dow Jones & Company, Inc. All Rights Reserved. 87990cbe856818d5eddac44c7b1cdeb8 ウォール・ストリート・ジャーナル日本版 今すぐ購読する
$5 billion flurry of nearly identical Kalshi trades draws scrutiny
Traders on the prediction market Kalshi have made almost one million trades in a single market since August that were in nearly identical amounts, unusual activity that has caught the eyes of federal regulators and traders. A Wall Street Journal analysis of public trading data found that in recent weeks, more than one-third of trades on a market speculating on the price of the cryptocurrency ether consisted of rapid trades clustered around the same order size—$5,500.
$5 billion flurry of nearly identical Kalshi trades draws scrutiny
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$5 Billion Flurry of Nearly Identical Kalshi Trades Draws Scrutiny
The rapid trades—all at nearly $5,500—occurred in a single Kalshi market. The prediction market says the trades represent normal activity. Traders on the prediction market Kalshi have made almost one million trades in a single market since August that were in nearly identical amounts, unusual activity that has caught the eyes of federal regulators and traders.
$5 Billion Flurry of Nearly Identical Kalshi Trades Draws Scrutiny
The rapid trades—all at nearly $5,500—occurred in a single Kalshi market. The prediction market says the trades represent normal activity.
$5 Billion Flurry of Nearly Identical Kalshi Trades Draws Scrutiny
Bitcoin 2 hours ago Bitcoin Cleared $85,000 a Week After the CLARITY Act Died and the Fed Hiked. How High Can It Go? AOL - Sam Daodu • 2h The Bitcoin (CRYPTO:BTC) price hovers at $86,291 after surging about 14% from its September 15 close of $75,584, the day the Senate voted down the CLARITY Act.
Polymarket’s Rush to Grow Left a Door Wide Open For Fraudsters
In February, a company processing debit-card transactions for Polymarket’s U.S. betting platform delivered some alarming news: Fraudsters were flooding the app. Users were linking stolen debit cards to Polymarket US accounts, then trying to use them to make wagers and withdraw the money into clean cards or accounts they controlled. Thieves tried to make off with at least $10 million.
Polymarket's Rush to Grow Left a Door Wide Open For Fraudsters — WSJ
By Katherine Long, Caitlin Ostroff and Neil Mehta In February, a company processing debit-card transactions for Polymarket's U.S. betting platform delivered some alarming news: Fraudsters were flooding the app. Users were linking stolen debit cards to Polymarket US accounts, then trying to use them to make wagers and withdraw the money into clean cards or accounts they controlled. Thieves tried to make off with at least $10 million.
Donald Trump Jr.'s fund boosts Polymarket investment by around $300 million
The investment fund 1789 Capital, in which Donald Trump Jr. is a partner, is investing around $300 million into Polymarket, according to a person familiar with the matter. The investment is part of a $1 billion round led by 1789 that would value Polymarket at $21 billion, according to people familiar with the matter. Polymarket declined to comment. The investment will make 1789 one of Polymarket's largest backers.
トランプ氏長男のVC、ポリマーケットに3億ドル追加投資
This copy is for your personal, non-commercial use only. Distribution and use of this material are governed by our Subscriber Agreement and by copyright law. For non-personal use or to order multiple copies, please contact Dow Jones Reprints at 1-800-843-0008 or visit www.djreprints.com. https://jp.wsj.com/articles/donald-trump-jr-s-fund-boosts-polymarket-investment-by-around-300-million-c0ea18c5
Donald Trump Jr.’s Fund Boosts Polymarket Investment by Around $300 Million
Upcoming round led by 1789 Capital would value the prediction market at roughly $21 billion Polymarket held a promotional event at a Washington, D.C., bar in March. Graeme Sloan/Bloomberg News The investment fund 1789 Capital, in which Donald Trump Jr. is a partner, is investing around $300 million into Polymarket, according to a person familiar with the matter.
Donald Trump Jr.’s Fund Boosts Polymarket Investment by Around $300 Million
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Donald Trump Jr.'s Fund Boosts Polymarket Investment by Around $300 Million — WSJ
Donald Trump Jr.'s Fund Boosts Polymarket Investment by Around $300 Million — WSJ POLYMARKET By Neil Mehta, Dana Mattioli and Caitlin Ostroff The investment fund 1789 Capital, in which Donald Trump Jr. is a partner, is investing around $300 million into Polymarket, according to a person familiar with the matter. The investment is part of a $1 billion round led by 1789 that would value Polymarket at $21 billion, according to people familiar with the matter. Polymarket declined to comment.
JPMorgan ended banking relationship with Polymarket over regulatory concerns
JPMorgan Chase ended its banking relationship with prediction market Polymarket last October over regulatory concerns, according to people familiar with the matter. The move adds fuel to fights in Washington over debanking and growing nationwide scrutiny of prediction markets' business practices, though the bank still maintains some ties to Polymarket and other prediction-market companies.
Left-wing surge stalls in Wisconsin as Francesca Hong narrowly loses
MADISON, Wis.—Milwaukee County Executive David Crowley narrowly won the Democratic nomination for governor in this battleground state, upsetting Democratic socialist Francesca Hong and delivering a significant blow to the party's insurgent far-left flank. Hong, who led in polls ahead of Tuesday's primary, had the backing of many progressives and the socialist left. But she lacked support from some of the movement's top national names. Boosted by a late endorsement from Democratic Gov.
Left-Wing Surge Stalls in Wisconsin as Francesca Hong Narrowly Loses
Updated Aug. 12, 2026 3:51 am ET Democratic Wisconsin gubernatorial candidate David Crowley greets supporters at a campaign rally. Scott Olson/Getty Images MADISON, Wis.—Milwaukee County Executive David Crowley narrowly won the Democratic nomination for governor in this battleground state, upsetting Democratic socialist Francesca Hong and delivering a significant blow to the party’s insurgent far-left flank.
Left-wing surge stalls in Wisconsin as Francesca Hong narrowly loses
MADISON, Wis.—Milwaukee County Executive David Crowley narrowly won the Democratic nomination for governor in this battleground state, upsetting Democratic socialist Francesca Hong and delivering a significant blow to the party's insurgent far-left flank. Hong, who led in polls ahead of Tuesday's primary, had the backing of many progressives and the socialist left. But she lacked support from some of the movement's top national names. Boosted by a late endorsement from Democratic Gov.
WSJ ⟩ Kuidas Wall Streeti kauplemisrobotid Trumpi Truth Sociali postitustest kasumit lõikavad
Päevatoimetaja: Urho Meister urho.meister@postimees.ee Saada vihje THE WALL STREET JOURNAL TELLIJALE Artikli sisu pärineb partnerväljaandest The Wall Street Journal. Donald Trump on muutnud oma sotsiaalmeediaplatvormi korralikuks rahamasinaks. Foto: Getty Images via AFP / Scanpix Loe kokkuvõtet President Donald Trumpi sotsiaalmeediaplatvorm Truth Social müüb börsikauplejatele ülikiiret ligipääsu presidendi postitustele. Wall Street tegeles sellise kauplemisega aga juba varem.
How Wall Street’s Bots Are Cashing In on Trump’s Truth Social Posts
Traders who already monitor the president’s pronouncements with automated systems can pay for an ultrafast feed. At least five firms have signed up. President Trump on a trader’s screen on the floor of the New York Stock Exchange. Richard Drew/AP President Trump’s Truth Social is selling stock market traders superfast access to his posts on the platform. Wall Street was already in on that game.
How Wall Street's bots are cashing in on Trump's Truth Social posts
President Trump's Truth Social is selling stock market traders superfast access to his posts on the platform. Wall Street was already in on that game. Many big investment firms have developed automated systems to monitor Truth Social, detect important keywords and take action—often within a fraction of a second—such as initiating or canceling positions, traders said. A Wall Street Journal review of trading data shows how quickly some traders have pounced on the president's online comments.
How Wall Street’s Bots Are Cashing In on Trump’s Truth Social Posts
Traders who already monitor the president’s pronouncements with automated systems can pay for an ultrafast feed. At least five firms have signed up.
SEC expected to change quarterly earnings rule despite public backlash
Caitlin Ostroff, Corrie Driebusch The Securities and Exchange Commission is expected to move forward with a plan to make quarterly financial reports optional, despite being inundated with public comments that overwhelmingly oppose the idea. The proposed rule-change, unveiled by SEC Chairman Paul Atkins in May, would give public companies the option to disclose their financial results twice a year, rather than on a quarterly basis.
SEC Flooded With Complaints Over Plan to Scrap Required Quarterly Earnings
SEC Chairman Paul Atkins unveiled a proposed rule change in May. Ian Maule/Bloomberg News The Securities and Exchange Commission asked the public what it thought about its proposal to no longer require public companies to report quarterly financial results. More than 200,000 comments—overwhelmingly negative—rolled in. It is the most feedback the SEC has ever received on a proposal, people familiar with the matter said, and the SEC is still working to get it all posted on the agency’s website.
SEC flooded with complaints over plan to scrap required quarterly earnings
Caitlin Ostroff, Corrie Driebusch The Securities and Exchange Commission asked the public what it thought about its proposal to no longer require public companies to report quarterly financial results. More than 200,000 comments—overwhelmingly negative—rolled in. It is the most feedback the SEC has ever received on a proposal, people familiar with the matter said, and the SEC is still working to get it all posted on the agency's website.
SEC Expected to Change Quarterly Earnings Rule Despite Public Backlash
Most of the over 200,000 comments urged the agency not to make quarterly financial reports optional; Trump has long supported such a move
FIFA's prediction-market partner gets off to rocky start
Alexander Osipovich, Caitlin Ostroff Vukašin Petrović was elated when FIFA's official prediction-market partner told him he was set to win a ticket to the World Cup. But the ticket was never delivered. Now, the 24-year-old crypto trader from Serbia is one of a growing number of ADI Predictstreet users angered by the fledgling platform's shaky start. ADI Predictstreet, which is owned by Abu Dhabi's royal family, was virtually unknown until it struck the high-profile deal with FIFA three months ago.
FIFA’s Prediction-Market Partner Gets Off to Rocky Start
Vukašin Petrović was elated when FIFA’s official prediction-market partner told him he was set to win a ticket to the World Cup. But the ticket was never delivered. Now, the 24-year-old crypto trader from Serbia is one of a growing number of ADI Predictstreet users angered by the fledgling platform’s shaky start. Copyright ©2026 Dow Jones & Company, Inc. All Rights Reserved. 87990cbe856818d5eddac44c7b1cdeb8
Lawmakers Call for Federal Probe of Polymarket Over Deceptive Advertising
Two senators are calling for a federal investigation into Polymarket’s social-media promotion of fake bets following The Wall Street Journal’s reporting on the prediction market’s deceptive marketing practices.
起底Polymarket的欺骗性营销内幕
Polymarket在社交媒体上投放了大量展示虚假押注的视频。《华尔街日报》记者Neil Mehta为您解析如何识破造假视频。封面图片制作：June Bang 自2022年起，Polymarket已被禁止向美国用户提供该网站的交易服务。然而，《华尔街日报》(The Wall Street Journal)的一项调查发现，Polymarket正在社交媒体上开展一项秘密行动，以吸引美国人的眼球，该公司不仅花钱雇佣创作者在假网站上录制交易视频，还招募海外水军推波助澜，让这些视频在美国网络上疯传。 这一系列操作强化了外界对Polymarket的印象，即用户可以通过该平台又快又容易地赚钱；而眼下，该公司正企图将其离岸网站重新打入美国市场。针对本报的报道，Polymarket在一份声明中回应称，该公司“致力于维持准确、公平和透明的市场。我们身处一个快速增长的行业，并不断评估如何改善我们与受众的互动方式并赢得他们的信任。”该公司同时表示，将对当前仍在投放的宣传内容展开审核。Polymarket与《华尔街日报》的出版商道琼斯(Dow...
We Investigated Polymarket’s Deceptive Marketing Campaign. Here’s What We Found.
Polymarket has been banned from letting U.S. users trade on its website since 2022. But the company is waging a secret campaign for Americans' attention on social media, paying creators to film trades on fake websites and hiring overseas workers to make the videos go viral in the U.S., a Wall Street Journal investigation found.
They Looked Like They Were Getting Rich on Polymarket—but None of It Was Real
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In his videos, George Makihara appears to have a lucrative side hustle making bets on Polymarket. In January, the college student posted a video that showed him winning $100,000 on a wager that President Trump would publicly say the word “McDonald’s” that month. The bet was one of 145 that Makihara appeared to place on Polymarket’s website between January and mid-May, based on his videos—bets adding up to almost $410,000.
By Katherine Long Verified, Caitlin Ostroff Verified, Neil Mehta, Brenna Smith Verified, Audrey Valbuena, Drew An-Pham
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The Wall Street Journal
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Kevin Warsh on the Fed, in his own words
Caitlin Ostroff, Nick Timiraos Sixteen years ago, Kevin Warsh stood before a group of economists in New York City and delivered a speech titled “An Ode to Independence.” It was 2010, and the central bank had been drawn into propping up the economy after the greatest financial crisis in generations. Warsh worried that the more the Fed stepped in, the easier it would become for elected officials to avoid making difficult economic choices of their own. “Central bank independence is precious.
Kevin Warsh on the Fed, in His Own Words
Kevin Warsh is succeeding Jerome Powell as chair of the Federal Reserve. Andrew Harnik/Getty Images Sixteen years ago, Kevin Warsh stood before a group of economists in New York City and delivered a speech titled “An Ode to Independence.” It was 2010, and the central bank had been drawn into propping up the economy after the greatest financial crisis in generations.
Why Almost Everyone Loses—Except a Few Sharks—on Prediction Markets
John Pederson, 33, couldn’t work. The former Outback Steakhouse line cook was recovering from a car crash and running out of money. Kalshi, the prediction market, promised a quick way to fix that. He took out a variable-interest loan and started betting. At first, it worked. Pederson turned about $2,000 into close to $8,000 by betting on daily snowfall totals in Detroit, where he lives.
Why almost everyone loses—except a few sharks—on prediction markets
Caitlin Ostroff, Katherine Long, Neil Mehta John Pederson, 33, couldn't work. The former Outback Steakhouse line cook was recovering from a car crash and running out of money. Kalshi, the prediction market, promised a quick way to fix that. He took out a variable-interest loan and started betting. At first, it worked. Pederson turned about $2,000 into close to $8,000 by betting on daily snowfall totals in Detroit, where he lives.
Why almost everyone loses-except a few sharks-on prediction markets
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米反政府暴力が30年ぶり高水準、昨年は「火炎瓶の年」
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銃を持った男が25日、米ホワイトハウス記者会主催の夕食会の保安検査場を走り抜けようとした。ドナルド・トランプ大統領、JD・バンス副大統領、カシュ・パテル連邦捜査局（FBI）長官のほか数人の閣僚など複数の政権関係者が出席していたが、全員がシークレットサービスによって迅速に退避させられた。 31歳のカリフォルニア工科大学卒業生による犯行とみられるこの事件によって、米政治における暴力の激化が再び注目を集めている。1月にはバンス氏の自宅の窓がハンマーでたたき割られ、3月にはニューヨーク市のゾーラン・マムダニ市長の自宅付近で攻撃を企てたとして司法省が男2人を起訴した。 Copyright ©2026 Dow Jones & Company, Inc. All Rights Reserved. 87990cbe856818d5eddac44c7b1cdeb8
By Caitlin Ostroff Verified, Jaclyn Jeffrey-Wilensky Verified
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The Wall Street Journal (Japan)
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燃烧瓶之年：美国反政府暴力事件创30年新高
上周六，一名持枪分子硬闯白宫记者晚宴安检站。当时有多名政府高官在场，包括总统特朗普(Trump)、副总统JD·万斯(JD Vance)、美国联邦调查局(FBI)局长卡什·帕特尔(Kash Patel)以及数位内阁成员。特勤局特工迅速将所有人护送离场。 嫌疑人据称是一名31岁的加州理工学院(Caltech)毕业生。这起事件再次引发了公众对美国政治暴力不断升温的关注。今年1月，一名男子抡起锤子砸碎了万斯家的窗户。今年3月，美国司法部指控两名男子企图在纽约市市长佐兰·马姆达尼(Zohran Mamdani)的住所附近发动袭击。 Copyright ©2026 Dow Jones & Company, Inc. All Rights Reserved. 87990cbe856818d5eddac44c7b1cdeb8
The year of the Molotov cocktail: American antigovernment violence hits a 30-year high
Caitlin Ostroff, Jaclyn Jeffrey-Wilensky On Saturday, a gunman rushed a security checkpoint at the White House Correspondents' Dinner. Multiple administration officials were present, including President Trump, Vice President JD Vance, FBI Director Kash Patel and several cabinet members. All were quickly hustled out by Secret Service agents. The incident, allegedly perpetrated by a 31-year-old Caltech grad, has refocused attention on rising violence in American politics.
The Year of the Molotov Cocktail: American Antigovernment Violence Hits a 30-Year High
Created with Highcharts 9.0.1Domestic attacks and plots targeting the U.S. government Source: Center for Strategic and International Studies Created with Highcharts 9.0.1'05'10'15'20'251994'95200004812162024 incidents April 27, 2026 1:43 pm ET On Saturday, a gunman rushed a security checkpoint at the White House Correspondents’ Dinner. Multiple administration officials were present, including President Trump, Vice President JD Vance, FBI Director Kash Patel and several cabinet members.
How a Fringe Conspiracy Theory About Missing Scientists Got the FBI’s Attention
The FBI says it is leading an effort to identify any connections between scientists who are dead or missing. Kyle Mazza/TheNEWS2/ZUMA Press April 25, 2026 12:00 pm ET Private investigator Thomas McNally sees no link between the disappearance of Melissa Casias and some 10 other missing or deceased scientists. The internet disagrees. Casias’s family hired McNally to hunt for clues after the New Mexico administrative assistant vanished last June.
Shayne Coplan. Scommettiamo
Poco prima dell’alba del 13 novembre 2024 gli agenti dell’Fbi hanno sfondato la porta dell’attico di Shayne Coplan nel quartiere newyorchese di Manhattan, facendo irruzione nella sua camera da letto e sequestrando il suo telefono. Stavano indagando sulle possibili violazioni antiriciclaggio della Polymarket, la piattaforma di scommesse in criptovalute fondata da Coplan e che permette ai suoi utenti di puntare su qualsiasi cosa, dalle elezioni presidenziali al prossimo interprete di James Bond.
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Jason Zweig, Caitlin Ostroff I want to meet you! I've finally found a 100% safe investment with unlimited upside. It's the time I'm going to spend face-to-face with readers like you in real life! Please join us at the first of our WSJ Talks: The Intelligent Investor in New York later this month. It'll be an informal gathering featuring me and my supersmart colleague Caitlin Ostroff. We'll chat about investing in today's market and take your questions, too.
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