• Big-name hedge funds had a strong October.
• Markets were briefly choppy, but a US-China trade deal and strong corporate earnings helped stocks.
• Sign up for Business Insider’s daily markets newsletter here.

October was mostly treats instead of tricks for the biggest hedge funds in the industry.

Market volatility briefly reached its highest point since the spring rollout of President Donald Trump’s tariffs, but investor jitters dissipated quickly as the US and China came to a trade agreement.

The biggest players in the $5 trillion hedge fund industry finished October mostly positive, though few were able to match the returns of the S&P 500.

At Izzy Englander’s $79 billion Millennium, the firm managed to return 1.5% in October, according to a person familiar with the firm. That bumped its 2025 gains to 7.6%.

Citadel had one of its strongest months of the year, with all five strategies making money across Ken Griffin’s $69 billion firm, a person with knowledge of the matter said. The flagship Wellington fund gained 1.8% and is up 6.8% year-to-date.

Its Tactical Trading fund, which blends its quant and fundamental stock-picking teams, gained 2.7% and is up 13.4% year-to-date; its equities fund gained 2.3% and is up 10.4% on the year; and its fixed-income fund gained 1.1% and is up 7.3% year-to-date.

Dmitry Balyasny’s $29.5 billion firm is now up 12.5% on the year after a 2.4% gain last month, a person close to the manager said. Michael Gelband’s ExodusPoint continued its strong year with another positive month, and the New York-based firm is now up 14.2% year-to-date, a person close to the manager said.

The S&P 500 hit new highs after a monthly gain of 2.3%, which was partially driven by strong earnings growth from the world’s largest companies. A review by the London Stock Exchange Group found that roughly 83% of S&P 500 companies that reported earnings so far in the fourth quarter have beaten estimates.

For the year, the index is up more than 16%.

Still, the industry overall is in a good place. Citco, a fund administrator with trillions of assets under administration, said in a recent report that 2025 is on pace to be the best year for hedge funds since 2020.

The managers mentioned declined to comment.

Editor’s note: This story was originally published on November 4 at 7:06 am. New figures have been added to the table below as they have been learned.

• Generative AI is becoming a headache for the marketplace quality team at TikTok Shop.
• Fraudsters are using generative AI to try to list fake brands or sell dupe products on Shop.
• TikTok exec Nicolas Waldmann said the company is mixing AI and human moderation to combat fraud.

AI-generated “slop” isn’t just mucking up our social feeds with deepfakes and other unsavory content. It’s also becoming a real problem for marketplace quality teams at e-commerce platforms like TikTok Shop.

Fraudulent sellers are using generative AI tools to make fake brands or dupe products in an attempt to get users to pay for goods that don’t actually exist, said Nicolas Waldmann, who leads TikTok Shop’s governance and experience external affairs team.

“It’s organized crime, to be honest,” Waldmann said. “They’re trying to basically go through and sell, and of course, never deliver anything, and then run with the money.”

While this type of e-commerce fraud has been around for years, generative AI has increased the sophistication of the methods that bad actors use to try to trick moderation teams on platforms like TikTok Shop or Amazon, Waldmann said.

TikTok uses a mix of human and AI moderation to help track down fraudulent accounts and listings. The company has its own in-house detection tools, as well as partnerships with outside firms to manage tasks like authenticating pre-owned luxury goods.

“We use AI to basically deal with AI,” Waldmann said.

In a new report published Thursday, the company said it had rejected 70 million products and removed 700,000 sellers for various policy violations in the first six months of 2025.

TikTok Shop is a top priority at the social-video company, which has set ambitious growth targets that have been challenging for its US team to hit. Last year, the company drove $100 million in single-day sales on Black Friday in the US.

The company has run into a variety of marketplace quality challenges since it began testing its e-commerce tool in the US in 2022. While TikTok has a lengthy list of prohibited items listed on its website, savvy operators have still managed to break through its filters to sell items like THC syrup and sex toys. “Dupes,” or knockoff versions of household-name items, have also created headaches for the social-shopping app. The company’s automated enforcement has irked some sellers in the past who said they were hit with violations without a clear explanation.

• New York City elected Zohran Mamdani, a democratic socialist, as its next mayor.
• Business leaders including Bill Ackman, Ken Griffin, and Andrew Yang congratulated Mamdani on his win.
• Some high-profile figures, like Elon Musk, came out against Mamdani.

Zohran Mamdani is the next mayor of New York City, and the congratulations have started to roll in from some business leaders.

Mamdani’s progressive agenda, which includes freezing rent, establishing city-owned grocery stores, free child-care, and taxing New York’s millionaires a flat 2% tax, has put some on Wall Street on edge. The 34-year-old mayor-elect has also said he doesn’t believe billionaires should exist.

Some high-profile business leaders came out against Mamdani prior to election night, throwing their support behind former Democratic Gov. Andrew Cuomo.

Billionaires like Bill Ackman, Mike Bloomberg, and Airbnb cofounder Joe Gebbia poured millions into pro-Cuomo groups. On Monday, Tesla CEO Elon Musk urged in a post on X to “VOTE CUOMO!”

Wall Street, however, isn’t unanimously anti-Mamdani. An analysis by Business Insider previously found that back-office workers on Wall Street overwhelmingly donated to the democratic socialist.

Yasser Salem, a former McKinsey executive and Mamdani’s “CEO whisperer,” told Business Insider that some executives are open to a few of Mamdani’s proposals, including free childcare, which could alleviate some of their employees’ financial burdens.

Here’s what business leaders are saying about New York City’s mayor-elect:

Jamie Dimon

In an interview with CNN on Wednesday, JPMorgan CEO Jamie Dimon said that he won’t make “quick decisions” about the bank’s future in New York because of Mamdani’s win.

“He’s a young man. Will he get good at it?” Dimon said about Mamdani making and implementing good policies. “I see a lot of people in big jobs, including political jobs. They grow into it.”

He added, “I’ve seen a lot of people. They kind of swell into the job. They get worse. They, you know, it all becomes about them.”

“I’m hoping he’s the good one and that will be important for the future in New York,” he said.

In his first press conference since being elected on Tuesday night, Mamdani mentioned the JPMorgan CEO and said, “I look forward to meeting with Jamie Dimon and meeting with anyone who is concerned about the future of our city, and is invested in the vitality of that same city.”

Bill Ackman

Bill Ackman, the CEO of Pershing Square Capital Management, spent a total of $1.75 million over the last year to keep Mamdani from becoming mayor, including $500,000 during the Democratic primary and $1.25 million in the general election.

On Tuesday night, Ackman wrote on X: “Congrats on the win. Now you have a big responsibility. If I can help NYC, just let me know what I can do.”

He expanded on that message in a follow-up post on Wednesday, writing that he cares “enormously” about the city and that Mamdani’s win was “decisive.”

“While I did not support Mamdani for mayor and have concerns about the unintended and negative consequences of his policies, I want to do everything I can to help NYC regardless of who are mayor is,” Ackman wrote.

Ackman has been a vocal opponent of Mamdani and publicly encouraged Sliwa to drop out of the race.

Mamdani singled out Ackman on the stump, naming him among the billionaires who oppose his candidacy. He has also mocked the hedge fund manager for his “1000-word tweets.”

Ackman is worth $8.44 billion, per Bloomberg.

Ken Griffin

Billionaire Ken Griffin, founder and CEO of hedge fund Citadel and market maker Citadel Securities, said he’s praying for the people of New York City.

“For the people of New York, I pray that the policies Mamdani uses to govern and lead New York are different than the talking points he used to win the mayoral race,” Griffin said Wednesday at the America Business Forum in Miami. “The people of New York deserve better.”

Griffin, one of the biggest donors to the GOP, was asked whether New York’s direction could prompt an exodus to cities like Miami. He moved Citadel’s headquarters from Chicago to Miami in 2022, over concerns about rising crime.

“You can’t live in a city awash in violent crime and feel proud to call that place home,” he said, adding that Florida is a great place to live.

“I really hope that when Mamdani thinks about leadership, he thinks about the right role models,” Griffin added. “There’s a lot to copy from our great state of Florida and from this great city of Miami.”

James Whelan

In a statement on Tuesday night, James Whelan, the president of the Real Estate Board of New York, said: “We congratulate Mayor-elect Mamdani on his victory.”

He added: “REBNY is prepared to work with the next mayor to address the issue of housing affordability and other challenges facing our city.”

Among his proposals, Mamdani plans to address the city’s housing crisis by tripling its production of publicly subsidized, rent-stabilized homes, at 200,000 new units over the next 10 years.

The plan would benefit households that make less than $70,000 a year, and it would cost the city $100 billion over the next decade.

He also plans to freeze rent for the city’s one million rent-stabilized units.

Andrew Yang

Andrew Yang, the former presidential candidate and the CEO of Noble Mobile, wrote in a post on X on Tuesday night: “Zohran Mamdani is the mayor-elect of New York City – and the hard part almost certainly lies ahead.”

In an edition of his newsletter published at the end of June, Yang said he predicted a “walkover” for Mamdani in the November election. He added that he met the mayor-elect before his campaign, and wrote: “I found him to be a good person who wants good things for people. He’s a sincere and talented messenger. He is positive and not the least bit hateful or corrupt.”

Alex Soros

Alex Soros, son of billionaire George Soros and chair of the $25 billion Open Society Foundations, wished Mamdani congratulations on X.

“So proud to be a New Yorker! The American dream continues!” he wrote in a post.

John Catsimatidis

John Catsimatidis, a New York City real estate and grocery store magnate, told Business Insider after Mamdani’s victory that he was skeptical of the mayor-elect’s plans for the police department and taxes.

Catsimatidis said that he expected the “bleed” of businesspeople from New York to states like Florida to continue under a Mamdani administration. “I don’t want to keep all my eggs in one basket in New York, so let me diversify to other states,” he said, describing the thinking of those who might consider leaving the city.

In June, Catsimatidis said that he would sell or close Gristedes, one of the New York supermarket chains that he owns, if Mamdani became mayor. At the time, Catsimatidis cited concerns about Mamdani’s plan to open city-run grocery stores if elected.

On Wednesday, the day after Mamdani’s victory, Business Insider asked Catsimatidis if he planned to sell Gristedes.

“Let’s see what Mr. Mamdani does,” Catsimatidis said. He said he wants to see if Mamdani makes good on his campaign promise of city-run stores.

“Remember the old expression, ‘You can’t fight City Hall,'” he added.

• Microsoft AI CEO Mustafa Suleyman announced the MAI Superintelligence Team on Thursday.
• “We reject narratives about a race to AGI,” Suleyman wrote, instead seeing it as a “deeply human endeavour.”
• Meta launched its own superintelligence lab earlier this year, led by Scale AI cofounder Alexandr Wang.

Four months after Meta announced its superintelligence lab, Microsoft is starting its own team.

Microsoft announced the MAI Superintelligence Team on Thursday, which will be led by Mustafa Suleyman, the CEO of Microsoft AI. Suleyman wrote in a blog post that the team aims to be the “world’s best place to research and build AI, bar none.”

“I think about it as humanist superintelligence to clearly indicate this isn’t about some directionless technological goal,” Suleyman wrote. “We are doing this to solve real concrete problems and do it in such a way that it remains grounded and controllable.”

“We are not building an ill-defined and ethereal superintelligence; we are building a practical technology explicitly designed only to serve humanity,” he added.

Microsoft did not respond to a request for comment from Business Insider.

Microsoft’s announcement comes just four months after the launch of Meta’s Superintelligence Lab, led by Scale AI founder Alexandr Wang.

“As the pace of AI progress accelerates, developing superintelligence is coming into sight,” Meta CEO Mark Zuckerberg wrote in a memo at the lab’s launch. “I believe this will be the beginning of a new era for humanity, and I am fully committed to doing what it takes for Meta to lead the way.”

In October, Meta laid off 600 employees from its superintelligence division.

Microsoft also appears to be trying to set itself apart from other AI rivals by emphasizing what it says will be its careful approach to pursuing superintelligence.

“In doing this we reject narratives about a race to AGI, and instead see it as part of a wider and deeply human endeavour to improve our lives and future prospects,” Suleyman wrote in his blog post.

“We feel a deep responsibility to get this right.”

Anthropic has taken a somewhat similar humanist approach, stating it wants to ensure “sophisticated AI systems remain beneficial to humanity.” As for superintelligence, CEO Dario Amodei said it could arrive as soon as 2026.

OpenAI cofounder and former chief scientist Ilya Sutskever is also involved in the superintelligence game. In 2024, Sutskever started his own research lab, Safe Superintelligence Inc., after leaving OpenAI.

Microsoft recently signed a new agreement with OpenAI, which it has invested billions in, that gives Microsoft a roughly 27% stake in OpenAI’s newly structured for-profit public benefit corporation.

As the two AI shops have become increasingly competitive even while partnered, Suleyman described it like “siblings” with a good relationship who sometimes “squabble.”

Do you work on a superintelligence team? Reach out to the reporter from a non-work device at hchandonnet@insider.com or at henrychand.30 on Signal.

• Some startups have found Amazon’s AI chips lag behind Nvidia’s GPUs in performance.
• AWS Trainium chips aim to offer a cost-effective alternative to Nvidia GPUs.
• Amazon’s AI chip market share is low, with Nvidia dominating at over 78%.

Amazon is counting on in-house AI chips to fuel its next phase of profitable growth. A recent internal document shows the cloud giant is still playing catch-up to Nvidia‘s dominant GPUs.

AI startup Cohere found that Amazon’s Trainium 1 and 2 chips were “underperforming” Nvidia’s H100 GPUs, according to an internal “confidential” Amazon document from July, obtained by Business Insider. Cohere reported that access to Trainium 2 was “extremely limited” and plagued by frequent service disruptions, the document also noted.

The “performance challenges” with Cohere were still under investigation by Amazon and its chip group Annapurna Labs, but progress on these issues was “limited,” the official document stated.

Stability AI, a well-known startup that generates AI images, had similar concerns. It concluded that Amazon’s Trainium 2 chips underperformed Nvidia’s H100 GPUs on latency, making them “less competitive” in terms of speed and cost, the document also warned.

An essential ingredient

Amazon’s homegrown Trainium chips are an essential part of the company’s effort to compete in the AI-cloud race. The early success of Amazon Web Services, especially its profitability, was based on designing its own data-center chips, rather than paying Intel for these pricy components. In the new generative-AI era, Amazon is trying to avoid paying for expensive Nvidia GPUs, while still providing cloud customers with powerful AI services.

If some AWS customers don’t want Trainium, and insist that AWS run their AI cloud workloads using Nvidia gear, that could undermine Amazon’s future cloud profits because it will be stuck paying more for GPUs.

The customer complaints highlighted internally by Amazon reveal the steep challenge it faces in matching Nvidia’s performance and getting profitable AI workloads running on AWS. This also underscores AWS’s ongoing challenges among startup customers, a segment that has long been its core market.

Feedback and Trainium 3

An Amazon spokesperson said the company is “grateful” for customer feedback that helps make its chips “even better and more widely used.”

The Cohere case is “not current,” the spokesperson added, while noting that Trainium and its other in-house AI chip, Inferentia, “have achieved great results” with customers including Ricoh, Datadog, and Metagenomi.

“We’re very pleased with the growth and adoption we’re seeing for Trainium 2, which at this stage is primarily used by a small number of very large customers like Anthropic,” this spokesperson wrote in an email to Business Insider.

AWS claims its in-house AI chips offer 30% to 40% better price performance than the current generation of GPUs. The company has incredible chip-design talent and is working on new generations of these crucial components.

“We expect to accommodate more customers starting with Trainium 3, previewing later this year,” the spokesperson said. “We’ll accomplish that as we always do by listening to our customers and remaining vocally self-critical with each other as we continue innovating to give more customers access to chips with the best possible price and performance.”

Last week, Amazon CEO Andy Jassy said during the company’s earnings call that Trainium 2 chips are “fully subscribed” and are now a “multibillion-dollar” business. Spokespeople for Cohere and Stability AI didn’t respond to requests for comment.

Long-standing complaints

Other AWS customers have also complained about Amazon’s AI chips.

According to the July document, a startup called Typhoon found Nvidia’s older A100 GPUs to be as much as three times more cost-efficient than AWS’s Inferentia 2 chips for certain workloads.

Similarly, a research group called AI Singapore determined that AWS’s G6 servers, equipped with Nvidia GPUs, offered better cost performance than Inferentia 2 across multiple use cases. (Inferentia chips are used for running AI models, a process known as inference, while Trainium chips focus on training models).

Last year, Amazon cloud clients also cited “challenges adopting” its custom AI chips, creating “friction points” and contributing to low usage, Business Insider previously reported.

These struggles are reflected in market share. Nvidia dominates AI chips with more than 78% of the market. That’s followed by Google and AMD, each with just over 4%, according to research firm Omdia. AWS’s chips ranked sixth, with 2% of the market.

No Trainium for OpenAI

A new $38 billion partnership between AWS and OpenAI illustrates Amazon’s challenges here. The deal involves AI cloud servers that only contain Nvidia GPUs, with no mention of Trainium processors.

The lack of Trainium in the OpenAI deal “could be viewed as disappointing,” Mizuho analysts wrote after the deal was announced this week.

Perhaps even more damning, these analysts wrote that it was “logical” for OpenAI to start with Nvidia GPUs.

Nvidia’s chips not only deliver superior performance but also come with a widely adopted platform, CUDA, that many developers already know and use. That familiarity is especially valuable when teams are building large, high-risk AI projects, where reliability and existing expertise can make a crucial difference.

In the July document, Amazon employees noted that technical limitations and other comparative issues between its custom AI chips and Nvidia’s GPUs have become “critical blockers” for customers thinking about switching to AWS chips.

Bank of America analysts were cautious about Tranium’s progress last month. In a note published in late October, they warned that investors have been “skeptical” about Trainium’s capabilities, and it was “unclear” whether strong demand will materialize “outside of Anthropic.”

Anthropic and Project Rainier

Trainium’s most high-profile customer is Anthropic, the AI startup behind the powerful Claude models. AWS recently rolled out Project Rainier, a giant data center project that includes a cluster of half a million Trainium chips that will be exclusively used to train Anthropic’s next-generation AI model. Anthropic is expected to deploy more than 1 million Trainium 2 chips by the end of the year.

Anthropic is one of the world’s leading AI labs, regularly challenging OpenAI with state of the art models. If Anthropic can make Trainium chips work, that would be a huge boost to Amazon’s efforts here. But the jury is still out on this.

Some investors were caught off guard last month by Anthropic’s move to broaden its partnership with Google, which provides its own in-house AI chips known as TPUs. Amazon’s stock slipped following this news, although Anthropic emphasized that it will continue using Trainium.

Anthropic has also publicly acknowledged the complexity of using multiple chip architectures, detailing related outages in a September blog post.

Amazon’s spokesperson told Business Insider that Anthropic is continuing to expand its use of Trainium chips and emphasized the company’s commitment to offering customers a range of hardware options across its cloud services.

During an earnings call with analysts last week, Jassy underscored AWS’s focus on offering “multiple chip options.” The goal is not to replace Nvidia, but to give customers more choice, a strategy AWS follows in other parts of cloud computing, he said.

“In the history of AWS, it’s never just one player that over a long period of time has the entire market segment and then it can satisfy everybody’s needs on every dimension,” Jassy said.

Amazon shares surged the next trading day, after it reported AWS revenue grew 20% to $33 billion last quarter, the fastest pace of growth since 2022. That’s still slower growth than rivals such as Microsoft and Google Cloud, on a percentage basis.

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