Caitlin Ostroff

Following money for @WSJ using words, numbers and code. Co-founder: @jourmentors. Tips: ∑: @TheAlligator, @MiamiHerald

[The Wall Street Journal @WSJ]

Insurers warn of fraud and exorbitant charges from providers, including one that stuck a parent with a surprise $911,400 bill. https://t.co/EJu7UEFOyc

[Alexander Osipovich @aosipovich]

Looking to trade on Polymarket? Here's the fine print: if your bet gets disputed (eg, because it's unclear if an agreement is a "ceasefire") the decision is up to anonymous holders of UMA, a digital token, who may have conflicts of interest. With @skesslr https://t.co/KNbO9UjZWt

[Sam Kessler @skesslr]

When a @Polymarket result is disputed, it goes to a decentralized panel of judges.

But the system is rife with conflicts: ~60% of judges were linked to Polymarket accounts, and in nearly 20% of disputes we found judges tied to bets on the very markets they were deciding.

w/ @aosipovich

https://t.co/9vTGSMmFcn

[Rebecca Ballhaus @rebeccaballhaus]

"In one meeting, Trump passed a stack of news articles he and other senior officials thought threatened national security to Blanche with a sticky note on it that said 'treason,' another administration official said." https://t.co/n06XSgZhcN

[Neil Mehta @neilmhta]

Who wins on prediction markets? High-frequency traders.

We examined 1.6 million Polymarket wallets and found that the top 0.1% highest-frequency traders are by far the most likely to turn a profit.

One of those traders is Jonathan Stall-Ryan (pictured), whose firm of around a dozen college students turned $1,000 into seven figures. They're one of the top crypto traders on Kalshi and make tens of thousands of trades a day.

[Amol Sharma @asharma]

Join our team and write about the people and forces shaping markets. Huge bets on AI. Macro trades affecting nations. Succession dramas. Individual investors making exotic wagers. Requires first-class reporting and the writing to do it justice. https://t.co/qt8uh4eGAk

[Caitlin Ostroff @ceostroff]

The U.S. government says its agents are under attack. Most of the alleged culprits in the tweets were U.S. citizens.

From my @WSJ colleagues @noslouch, @brenna__smith, @HannaCritch, @bellecushing and @emmatscott
https://t.co/7D1gEGDvUy

[Caitlin Ostroff @ceostroff]

My friend wrote a book and you should buy it 📚

[Evan Gershkovich @evangershkovich]

Sorry. Phone died. What did I miss? In the meantime, I wrote a book

[Evan Gershkovich @evangershkovich]

Sorry. Phone died. What did I miss? In the meantime, I wrote a book

[Katherine Long @ByKLong]

NEW: A fraternity that counts Jeff Bezos' stepson as a member under investigation for insider trading. Polymarket-branded beer pong sets. $20,000 in funding to open a prediction market club.

Here's how prediction markets are gaining ground on campus.
https://t.co/046UIRoXaZ

[Rebecca Ballhaus @rebeccaballhaus]

“We know this shouldn’t be allowed,” said one brother involved. “People are like, is this insider information? Is this regulated? You feel like you’re doing something you’re not supposed to. It feels like someone should stop you.”

Must-read: https://t.co/9mL0j6x11L

[Caitlin Ostroff @ceostroff]

ICYMI: My latest with @sgurman

[The Wall Street Journal @WSJ]

The Justice Department has withheld thousands of documents from the Epstein files, including FBI documents that detailed a woman’s unverified allegations of sexual misconduct against President Trump, according to a review by WSJ. https://t.co/eHyb4LcnRs

[Alexander Osipovich @aosipovich]

Did Polymarket finally go too far? It's just removed a betting market on nuclear detonation, amid intense debates over the ethics of war betting and the risks of insider trading on military strikes. From @ceostroff https://t.co/0LCgFxwJ1M

[Caitlin Ostroff @ceostroff]

My latest with the great @sgurman

[Caitlin Ostroff @ceostroff]

New: After a @WSJ analysis identified more than 40,000 files that appeared to be missing from the DOJ’s website, a DOJ spokeswoman said that “47,635 files were offline for further review and should be ready for re-production by the end of the week.”

https://t.co/mWli4A2S6o

[Caitlin Ostroff @ceostroff]

New: After a @WSJ analysis identified more than 40,000 files that appeared to be missing from the DOJ’s website, a DOJ spokeswoman said that “47,635 files were offline for further review and should be ready for re-production by the end of the week.”

https://t.co/mWli4A2S6o

[Alexander Osipovich @aosipovich]

Kalshi has posted its first disciplinary actions, against a former longshot candidate the California governor and a MrBeast employee. My colleague @kryshur reports on the brave new world of prediction-market enforcement actions https://t.co/LVdZEPdQ9u

[Alexander Osipovich @aosipovich]

It's one of the wackiest corners of prediction markets: "mentions", where traders bet on phrases that politicians and celebrities say at upcoming events. Will the words "insider trading" and "manipulation" appear in this story? With @ceostroff @ByKLong https://t.co/eKv8m9en1j

[Caitlin Ostroff @ceostroff]

@AndrewForce8 @khadeeja_safdar It’s in print today!

[Caitlin Ostroff @ceostroff]

On May 3, 2016, Epstein sent an email to Kathy Ruemmler. He wrote that Jean-Luc Brunel was planning to go to prosecutors the following week and one of Brunel’s friends had “asked for 3 million dollars so that Jean Luc would not go in.”

w/@khadeeja_safdar
https://t.co/Fv2xMGZLlt

[Caitlin Ostroff @ceostroff]

@ryangrim An effort by so many in the newsroom. Thank you for reading!

[Caitlin Ostroff @ceostroff]

@emsteck @khadeeja_safdar Thank you for reading!