OpenAI could now be the world’s most valuable startup, ahead of Elon Musk’s SpaceX and TikTok’s parent company ByteDance, after a secondary stock sale designed to retain employees at the ChatGPT maker.

Current and former OpenAI employees sold $6.6 billion in shares to a group of investors, pushing the privately held artificial intelligence company’s valuation to $500 billion, according to a source with knowledge of the deal who was not authorized to discuss it publicly.

The investors buying the shares included Thrive Capital, Dragoneer Investment Group and T. Rowe Price, along with Japanese tech giant SoftBank and the United Arab Emirates’ MGX, the source said Thursday.

The valuation reflects high expectations for the future of AI technology and continues OpenAI’s remarkable trajectory from its start as a nonprofit research lab in 2015.

But with the San Francisco-based company not yet turning a profit, it could also amplify concerns about an AI bubble if the generative AI products made by OpenAI and its competitors don’t meet the expectations of investors pouring billions of dollars into research and development.

OpenAI CEO Sam Altman has sought to dismiss those concerns, most recently last week, when he toured a massive data center complex being built to run the company’s AI systems in Abilene, Texas.

“Between the ten years we’ve already been operating and the many decades ahead of us, there will be booms and busts,” Altman said after being asked about a bubble. “People will overinvest and lose money, and underinvest and lose a lot of revenue.”

He added that “we’ll make some dumb capital allocations” and there will be short-term ups and downs but that “over the arc that we have to plan over, we are confident that this technology will drive a new wave of unprecedented economic growth,” along with scientific breakthroughs, improvements to quality of life and “new ways to express creativity.”

Just this week, the company launched two different business ventures, one a partnership with Etsy and Shopify for online shopping through ChatGPT and another a social media app, Sora, for generating and sharing AI videos.

OpenAI has been struggling to offer investors and staff the same perks and compensation as the publicly traded tech giants with which it competes. Facebook parent Meta Platforms, in particular, has been on a hiring spree for elite AI engineers and in June made a $14.3 billion investment in AI company Scale that recruited its CEO Alexandr Wang.

OpenAI’s for-profit subsidiary, valued at $500 billion, is technically controlled by the board of OpenAI’s nonprofit and both are still bound to pursue the nonprofit’s charitable purpose.

OpenAI’s partnerships with major companies and its plans to change its corporate structure have drawn the scrutiny of regulators, including the attorneys general of California and Delaware, who oversee charitable organizations that operate or are incorporated in their states.

The company has made big deals in recent weeks with Oracle and SoftBank, its partners on a data center venture called Stargate, and with chipmaker Nvidia, which makes the specialized AI chips those data centers need. At the same time, it has lessened its reliance on longtime backer Microsoft.

In September, OpenAI announced it had reached a tentative agreement with Microsoft about the future stake of its nonprofit in its for-profit corporation but released few details.

It also opened applications for nonprofits to apply for $50 million in funding from OpenAI, an effort it launched in response to the recommendations of an advisory board. The grants will go toward projects that increase public understanding of AI, support the design of AI for uses that communities want and increase economic opportunity. The deadline to apply closes on Oct. 8.

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Virgin Media O2 (VMO2) has announced the successful switch-on of a first-of-its-kind Giga Site utilising newly acquired spectrum, marking a step forward in delivering faster and more reliable mobile connectivity across the UK.

The site, in Paddington, London, is based on Nokia dual-band massive multiple-input multiple-output (massive MIMO) technology that VMO2 says will bring customers an enhanced and more reliable mobile experience.

The Giga Site combines low, mid and high-band spectrum with Nokia’s massive MIMO technology, said to use a large number of antennas to significantly improve 5G network performance by boosting capacity, spectral efficiency, data rates and coverage.

The site is said to be able to deliver more than 10Gbps of throughput, which VMO2 noted was more than the entire O2 UK network carried at the peak of the London 2012 Olympics, and is enough to support 2,000 simultaneous 5Mbps HD video streams.

By bringing together different spectrum bands on one mast, the operator says it can offer strong, reliable signal to a large area. The single site is using a combination of low-band spectrum to provide broad coverage, mid-band to offer additional capacity, and high-band to give customers very fast speeds.

The spectrum used includes that obtained as part of VMO2’s recent deal with Vodafone UK to acquire 78.8 MHz of spectrum, bringing the operator’s total spectrum holding to approximately 30% in the UK.

Following what it observed was many months of detailed technical planning, signal at the site was put to use just one minute after it was transferred. VMO2 says it will continue to deploy this spectrum over the medium term. In addition, the operator plans to install 1,000 of these cutting-edge sites across the country next year, boosting mobile connectivity and capacity in the UK.

Robert Joyce, director of mobile access engineering at O2, said: “The switch-on of our first Giga Site here in central London is a really important demonstration of how we are investing and innovating to continue improving our mobile network and customer experience. These new sites will deliver faster speeds, greater capacity and more reliable connections for our customers. As we carry out upgrades and roll out hundreds more Giga Sites across the country, we’ll put our new spectrum to work, helping us keep improving mobile connectivity nationwide.”

Mark Atkinson, head of radio access networks at Nokia, added: “Our partnership with Virgin Media O2 to implement Giga Sites reflects our commitment to helping our customers differentiate with superior performance.

“This is one of Europe’s first dual-band massive MIMO deployments combined with our TDD carrier aggregation solution, which showcases how our latest high-performance radios and versatile carrier aggregation solutions allow operators to fully harness the power of their spectrum, enabling the next wave of 5G services.”

The upgrades are part of Virgin Media O2’s mobile transformation plan, which will see the operator invest approximately £700m in 2025 to bolster its mobile network. The plan is focused on expanding 4G and 5G coverage, a dedicated small cells roll-out to boost capacity in dense urban areas, and solutions to address persistent network pain points including along railway lines, at airports, on motorways, and in stadiums and arenas.

When multiple people work together, things sometimes turn out better than doing the same task alone. Then, there are other times, when cooperation actually seems to hinder progress, making things much more inefficient.

To understand why this “cooperative advantage” manifests in some cases but not in others, a research group led by Assistant Professor Asuka Takai of the Graduate School of Engineering at Osaka Metropolitan University conducted a task where participants used a robotic arm to transport a rod while keeping it horizontal.

The study was published in The International Journal of Robotics Research.

The participants were told that the task would stop if the rod’s tilt exceeded a certain threshold. They compared performance between groups of two people working together and people performing the task alone.

To examine the effect of teamwork, the group created two conditions. In the “symmetric” condition, the axis of the rod was centered, meaning the task could be equally split between the two arms. In the other “asymmetric” condition, the rotation axis was off-center because the arms were different lengths. This meant that the participant assigned the shorter arm typically had to lead the one assigned the longer arm.

Under the asymmetric condition, the paired participants learned to adjust their movements with each trial to minimize the tilt of the rod. A natural division of roles emerged, with one partner taking the lead and the other providing support, leading to superior performance by the pairs compared to the individuals.

On the other hand, under the symmetric conditions, no division of roles was observed between partners. Under these conditions, pairs that did not exhibit clear role differences required more transportation time and trials than individuals.

Overall, pairs outperformed individuals when the two participants naturally assumed different roles, whereas individuals performed better than pairs when no such role differentiation occurred.

“The study confirmed that when a ‘leader–follower’ relationship naturally emerges under physically asymmetric conditions, cooperative performance improves,” Professor Takai explained. “Our findings suggest that role specialization, rather than paired interaction per se, was a key factor underlying superior performance.”

The group hopes that future research will explore how asymmetric dynamics, which foster leader–follower dynamics, could similarly enhance performance in rehabilitation and human–robot settings.

“This discovery is expected to be applied to collaborative design between humans and robots,” Professor Takai said. “A robot needs to know when to take on a task itself or hand it over to a human, which may require understanding subtle differences in how each can contribute to the task.”