2025 top stocks: AI cloud, defence and quantum computing named retail investors’ favourite themes

• Retail investors back AI data centres with Nebius Group crowned 2025’s top stock riser, with Oracle in 3rd place
• European defence stocks, including Leonardo and Rheinmetall, dominate the top risers
• Retail interest in quantum computing grows as IonQ and D-Wave Quantum make the risers list
• While Romanian investors continue to invest in technology and AI, outside the sector, Pepsi and Berkshire Hathaway are the biggest risers

The biggest investment themes among global retail investors in 2025 were AI data centres, European defence, and quantum computing, according to the latest data from trading and investing platform eToro.

eToro looked at which companies saw the biggest proportionate change in holders year-on-year (table 1), while also looking at the 10 most held stocks on the platform (table 3) to identify the key themes that caught retail investors’ attention in 2025.

AI infrastructure provider Nebius Group led the ‘top risers’ list with a 328% increase in holders in 2025. Oracle, also a key player in this industry, came third with a 228% year-on-year jump in holders. Despite talks of a bubble, eToro’s data suggests that retail investors’ interest in AI has not abated. Major AI stocks like Nvidia, which is the most held stock on the platform, rounded off the year with 21% more holders, while Meta, a frontrunner in AI technology, added 19% more holders.

European defence is another theme that dominated the top risers list. With the European Union proposing a €800 billion plan this year to rearm Europe, four European defence companies made the cut: Leonardo (4th place, +209%), Thales (7th place, +167%), Rheinmetall (8th place, +165%), and BAE Systems (10th place, +141%).

Lale Akoner, Global Market Strategist at eToro, said: “Retail investors remain constructive on AI, but 2025 shows a clear rotation within the theme. After a chip-led rally in previous years, investor attention has shifted toward infrastructure and enablers of AI deployment like Nebius Group and Oracle, fuelled by the massive surge in data centre investment around the world, which reached $61 billion in 2025 according to S&P Global. The data suggests that, despite valuation concerns, investors are increasingly differentiating between speculative AI exposure and businesses with clearer revenue visibility and capital intensity advantages.

“European defence stocks also gained momentum, and they are increasingly treated as a structural allocation in portfolios, as geopolitical tensions are reshaping long-term market opportunities. The combination of clearer policy direction, and multiyear spending programs have improved earnings visibility for the sector. Companies like Thales, Rheinmetall, Leonardo and BAE Systems have benefited from lucrative, multi-year contracts, reducing cyclicality and supporting the investment case for long-term investors.”

Retail investors also showed a growing appetite for the budding sector of quantum computing. Quantum computer makers IonQ  (+169%) and D-Wave Quantum (+149%) came in 6th place and 9th place respectively. Although not in the top 10, Rigetti Computing also saw a 138% increase in holders, ranking in 11th place.

Lale Akoner said: “The outlook improved for the quantum computing sector in 2025. While the sector is still high-risk and long dated, contract wins such as Rigetti’s which announced landmark purchase orders, including a $5.8 million contract with the US Air Force, helped anchor valuations in the sector. Retail investors appear increasingly willing to allocate selectively to frontier technologies where fundamentals, rather than hype, are starting to drive performance.”

In addition to these themes, UnitedHealth and Hims & Hers Health were two of the most popular stocks on eToro in 2025, as their holders increased by 273% and 197% respectively. Healthcare were not just bought but also sold by many, as 2025’s ‘top fallers’ list was led by TransMedics Group (-60% decrease in holders), Ulta Beauty (-53%), and ZEPP Health (-40%). All three saw significant gains in their stock price over the course of the year: 95% for TransMedics, 39% for Ulta, but most of all, 936% for ZEPP Health.

Top stocks in Romania

Romanian retail investors reacted similarly to their global counterparts (Table 4), but favoured the Chinese EV manufacturer Nio more than Tesla. Nvidia climbed from 3rd place at the end of 2024 to 1st place at the end of 2025 in the most-held ranking. Tesla on the other hand dropped from 1st place to 3rd place. The rise of AI also pushed up Amazon and Meta, while the Romanian-born unicorn UiPath sank further to the 7th position.

Looking at the top stock risers (Table 2), Romanian retail investors showed sustained appetite for the technology sector in 2025, with TSMC, Nvidia, Meta, and memory manufacturer Micron in the list. Netflix was the stock whose holders increased the most, by 25%. Outside the technology sector, PepsiCo and Warren Buffett’s Berkshire Hathaway were the companies that showed the largest increase in Romanian holders in 2025.

On the fallers side, (Table 2) we have also seen some reduction in positions in tech companies like Crowdstrike (27%) Samsung (27%), Airbnb (26%).  

Bogdan Maioreanu, eToro Market Analyst Romania, said: “Romanian retail investors showed that technology, together with AI, was the main field of interest in 2025. AI is still the main theme, but we are seeing growth in the broader field with silicon chip producers like TSMC and chip manufacturer technology companies like ASML.

Netflix showed the biggest percentage in gaining new investors, showing that the Romanians love their TV shows, while also paying attention to the company’s financials and its expansion plans, which translated to investing.  Romanian investors decreased their holdings in CrowdStrike and Samsung, among others, most likely taking profits after their rally, but high valuations, regulatory constraints or slowdown in profits may have also triggered the sales.

Looking at the broader perspective, Romanian retail investors are still trying to capitalize on the AI and technology sector advances in 2026 but are having a broader approach on the phenomenon, beyond the “Magnificent 7” stocks, which remain in the top 10 most held stocks on eToro platform. ”