Ideally, thematic ETFs capture long-term secular investment themes not fully represented by broad market or sector-based approaches. The best thematic index implementations make use of quantifiable measures such as revenue and market share to identify companies with meaningful exposure to specific themes. With emerging themes that are “pre-revenue” it is often a challenging exercise to identify the most influential players, requiring specialty data sources to make those determinations.
Although specific themes come in and out of favor, thematic investing is here to stay, as investors seek diversified exposure to hot new trends and industry disruption. Using Bloomberg ETF flow data, global flows into thematic ETFs surpassed $21 billion YTD, with approximately $11 billion in U.S. thematic flows. Thematic inflows are the most robust since 2021.
Top Themes Capturing Global Flows
At the top of the list globally are themes such as defense, artificial intelligence, and infrastructure. Let’s explore the ETFs in these top flow categories.
Defense
At the top of the U.S. defense category is the Select STOXX Europe Aerospace & Defense ETF (EUAD), which focuses on the rising defense opportunity rearming Europe and is up an impressive 84.8% YTD. Trailing slightly behind in terms of YTD performance is the Global X Defense Tech ETF (SHLD), which targets global defense technology exposure at 82.5%.
| Symbol | ETF Name | Total Assets | YTD Return | ER |
| EUAD | Select STOXX Europe Aerospace & Defense ETF | $1,244,690,000 | 84.82% | 0.50% |
| SHLD | Global X Defense Tech ETF | $5,332,620,000 | 82.46% | 0.50% |
| NATO | Themes Transatlantic Defense ETF | $62,776,100 | 51.59% | 0.35% |
| XAR | SPDR S&P Aerospace & Defense ETF | $4,675,110,000 | 49.02% | 0.35% |
| ITA | iShares U.S. Aerospace & Defense ETF | $12,079,500,000 | 45.91% | 0.38% |
| MISL | First Trust Indxx Aerospace & Defense ETF | $220,356,000 | 43.00% | 0.60% |
| PPA | Invesco Aerospace & Defense ETF | $6,776,900,000 | 36.70% | 0.58% |
| WAR | U.S. Global Technology and Aerospace & Defense ETF | $12,000,100 | 28.87% | 0.60% |
VettaFi, as of 10/15/25
Artificial Intelligence
Among AI-themed ETFs, the Roundhill Generative AI & Technology ETF (CHAT) tops this year’s performance leaderboard, gaining 53.6% and approaching the $1 billion mark in assets. It’s followed by the VistaShares Artificial Intelligence Supercycle ETF (AIS), a reasonable newcomer that launched last December, up 52.3%. There are many other ETFs not covered in this analysis given their short track record.
| Symbol | ETF Name | Total Assets | YTD Return | ER |
| CHAT | Roundhill Generative AI & Technology ETF | $959,308,000 | 53.61% | 0.75% |
| AIS | VistaShares Artificial Intelligence Supercycle ETF | $74,823,600 | 52.29% | 0.75% |
| ALAI | Alger AI Enablers & Adopters ETF | $278,663,000 | 41.29% | 0.55% |
| WTAI | WisdomTree Artificial Intelligence and Innovation | $403,416,000 | 34.27% | 0.45% |
| AIVC | Amplify Bloomberg AI Value Chain ETF | $33,794,800 | 34.19% | 0.59% |
| THNQ | ROBO Global Artificial Intelligence ETF | $301,368,000 | 33.08% | 0.68% |
| AGIX | KraneShares Artificial Intelligence & Technology ETF | $98,088,700 | 31.45% | 0.99% |
| AIQ | Global X Artificial Intelligence & Technology ETF | $6,482,100,000 | 29.04% | 0.68% |
VettaFi, as of 10/15/25
Infrastructure
In the category of global infrastructure the iShares Emerging Markets Infrastructure ETF (EMIF) is in the lead in terms of YTD performance (+23.6%). It’s followed by the ClearBridge Sustainable Infrastructure ETF (INFR) (+21.4%) and the SPDR S&P Global Infrastructure ETF (GII) up 20.6%.
| Symbol | ETF Name | Total Assets | YTD Return | ER |
| EMIF | iShares Emerging Markets Infrastructure ETF | $7,605,420 | 23.63% | 0.60% |
| INFR | ClearBridge Sustainable Infrastructure ETF | $10,754,800 | 21.36% | 0.59% |
| GII | SPDR S&P Global Infrastructure ETF | $625,610,000 | 20.59% | 0.40% |
| IGF | iShares Global Infrastructure ETF | $8,416,470,000 | 20.23% | 0.39% |
| PAVE | Global X US Infrastructure Development ETF | $9,691,710,000 | 18.36% | 0.47% |
| NFRA | FlexShares STOXX Global Broad Infrastructure Index Fund | $3,017,360,000 | 18.30% | 0.47% |
| IFRA | iShares U.S. Infrastructure ETF | $3,119,870,000 | 16.84% | 0.30% |
| RBLD | First Trust Alerian US NextGen Infrastructure ETF | $19,035,400 | 15.58% | 0.65% |
| TOLZ | ProShares DJ Brookfield Global Infrastructure ETF | $155,515,000 | 13.01% | 0.46% |
VettaFi, as of 10/15/25
Does It Pay to Go With the Flow?
In general, positive fund flows are an indicator of favorable sentiment toward a specific fund or investment category. ETFs in defense, AI, and infrastructure have been the positive beneficiary of flows this year. While large inflows could drive up prices in the underlying investments of an individual ETF, investors who target less popular funds with better exposures, characteristics, or performance may be better served from a long-term perspective.
A recent study published in the Wall Street Journal by Professor Derek Horstmeyer at George Mason University found that using real-time flows to inform the trading of mutual funds and ETFs can improve investment returns. However, if you use the prior month’s flows, that advantage disappears. Ultimately, while there is an information advantage to knowing where flows are going in real-time, investors may be better off focusing more on ETF due diligence as a selection criteria. The transparency of ETFs means you can take time to understand and know what companies and exposures you own.
For more news, information, and strategy, visit the Disruptive Technology Content Hub.
