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- At the ETFs in Depth flagship event hosted by Bloomberg in New York in December, industry experts discussed how ETF scale is reshaping portfolio construction across active, bond, income, and crypto strategies.
- Global ETF assets and trading volumes are scaling quickly, shifting ETFs from tactical exposure tools to structural building blocks in portfolio construction across asset classes.
- Model portfolios, index design, and cost discipline increasingly determine which ETFs attract sustained flows and long-term allocations from advisors and institutions.
As exchange traded fund (ETF) assets continue to grow, their impact is extending beyond exposure delivery to influence portfolio design and implementation. Investors are increasingly adapting frameworks to reflect that expansion. At the ETFs in Depth flagship event hosted by Bloomberg in New York in December, experts discussed the growth trajectory of this fund structure and how that scale is reshaping portfolio construction, from active management and model portfolios to fixed income and cryptocurrency exposure.
PRODUCT MENTIONS
How ETF growth is changing market structure
The recent growth in ETF adoption highlights how quickly this fund structre is gaining prominence. As Eric Balchunas, senior ETF analyst at Bloomberg Intelligence, points out, in 2024 global net inflows rose roughly 25% year-on-year to around $1.4 trillion, while trading volumes reached approximately $60 trillion, up 27%. Issuers launched more than 1,000 new ETFs during the year, a 45% increase over that period.
“The rise in trading activity is particularly telling,” says Eric Balchunas, senior ETF analyst at Bloomberg Intelligence. Notably, while ETF volumes have historically surged during periods of market stress, 2024’s increase occurred without a sustained spike in market volatility. According to Balchunas, that pattern suggests ETF usage is becoming more structural, rather than driven by short-term risk aversion.
How interest rate and recession risks affect ETF inflows
Despite persistent concerns around interest rates, recession risks and periodic “sell America” narratives, investors have remained steady buyers of ETFs, with flows concentrated in low-cost core equity exposure, gold and cash-flow-oriented products, according to Balchunas.
Notably, the primary beneficiaries have been the larger low-fee providers: “They have emerged as a market stabilizing force, creating something similar to the Fed put,” says Balchunas.
Beyond shifting market dynamics and the migration from mutual funds, policy proposals such as tax-advantaged investment accounts for newborns could further accelerate ETF inflows, he adds.
While the ETF market continues to expand, Balchunas notes that potential alternatives like direct indexing, where investors hold individual securities rather than a collective vehicle, and tokenization, which involves representing assets on blockchain-based platforms, have yet to gain meaningful traction.
Are equity ETFs still an anchor for investor allocations
Equity ETFs continue to capture the bulk of investor flows, reinforcing their role as the primary vehicle for long-term equity exposure, says Balchunas. The persistent correlation between movements in the S&P 500 and equity ETF inflows suggests investors are increasingly expressing buy-and-hold convictions through ETFs, even during periods of acute stress such as the Covid-19 selloff. Performance has been heavily shaped by the so-called Magnificent Seven, a group of dominant U.S. technology companies comprising Apple, Microsoft, Alphabet, Amazon, Nvidia, Meta Platforms and Tesla, which now account for roughly a third of the S&P 500. Comparisons with earlier episodes of market concentration, however, overlook important differences, experts point out.
Today’s index heavyweights are not narrowly focused giants, but diversified platforms spanning multiple large-scale businesses. Alphabet, for example, has acquired hundreds of companies over the past two decades, including YouTube, which would likely rank among the world’s largest listed companies if spun out. “Tech has become the new industrial base,” says Rick Rieder, Chief Investment Officer of Global Fixed Income at BlackRock, noting that this underlying diversification helps explain why equity ETFs have remained central to portfolio construction despite valuation concerns.
The role of model portfolios in determining ETF scale
As ETF allocations grow, model portfolios increasingly determine which products scale, says Richard K. Tseng Senior Portfolio Manager Team Lead at Bank of America Merrill Lynch, referring to pre-constructed investment frameworks designed by asset managers, advisors or platforms to define asset allocations and product selections for different investor objectives or risk profiles.
Portfolio construction focuses on balancing expense ratios, tracking error, trading costs and liquidity. While secondary-market volume matters, creation and redemption capacity remains critical. Index design also plays a central role, as small rule differences can lead to meaningful performance gaps over time. “Index design matters,” says Paul Salerno, Global Head of Index Sales and Relationship Management at Bloomberg. “For example, we created a taxable fixed income index intended to better reflect market structure by incorporating segments often excluded from traditional universal benchmarks, including Rule 144A bonds, TIPS and floating-rate notes,” he adds.
Within models, portfolios are typically built around low-cost core index exposure, with smaller satellite allocations used for income, leverage, tax planning or tactical positioning. Products that fit cleanly into these sleeves tend to gain adoption, while more complex strategies remain constrained.
“Portfolios are developed from the index first, and only then do we assess whether more complex products add sufficient value to justify their use,” says Riz Hussain, director and investment portfolio strategist at Charles Schwab & Co.
Buffer ETFs, which offer partial downside protection in exchange for capped upside over a defined period, are increasingly used as substitutes for portions of fixed-income allocations. More specialised strategies such as private credit remain constrained by structural issues like transparency and liquidity, according to Steve Laipply, Global Co-Head of iShares Fixed Income ETFs at BlackRock.
The growing role of actively managed ETFs in portfolios
Actively managed ETFs are drawing increasing attention. Data from Bloomberg Intelligence shows that currently about 33% of ETF inflows are now directed into active products, and roughly 83% of new ETF launches are actively managed.
Assets, however, remain concentrated elsewhere. Active ETFs still represent only about 10% of total ETF assets, indicating that managers are launching aggressively in response to early demand, even as scale remains limited.
Pricing discipline has become central to the category’s viability, particularly as active managers that have bet against the Magnificent Seven have underperformed. “Funds with low active share and benchmark-like returns have been forced to price closer to beta, while more differentiated strategies have retained some pricing power,” says Balchunas. With low-cost indexing making beta effectively free, investors are willing to pay only for clearly active — and successful — exposure.
How income strategies are driving the next phase of ETF innovation
Some of the most visible change in the ETF market is occurring in income strategies. The category has evolved from traditional dividend products to options-based income and, more recently, to structured or autocallable-style approaches often described as “Yield 3.0.”
This shift is being driven less by the largest index providers and more by specialist firms focused on options income and higher-yield structured products. Balchunas says several of these ETFs have attracted steady inflows, suggesting demand is durable. He also notes that the yield spectrum is also widening, ranging from semi-defensive structured income ETFs to more aggressive synthetic-yield products. While risk profiles vary widely, flows indicate that income has become a central axis of ETF development.
The growing role of crypto ETFs in institutional asset allocation
During the recent drawdown, only about 4% of assets exited the crypto market according to Bloomberg Intelligence The limited outflows suggest crypto is increasingly behaving like a mature asset class rather than a purely speculative trade,
To that end, that shift is reflected in policy changes at Vanguard, long one of the industry’s most conservative gatekeepers, which recently lifted internal restrictions around crypto exposure. Balchunas pointed to ETF flow data as further evidence that crypto is becoming more embedded in institutional portfolios. For example, IBIT, BlackRock’s spot Bitcoin ETF, has reached roughly $100 billion in assets and is now the firm’s top revenue-generating ETF among more than 1,000 products, despite being barely a year old.
From adoption to integration
If the past decade was defined by ETF adoption, experts point out that the next is likely to be defined by how those tools are deployed. Income strategies, active management and crypto are increasingly channelled through model-driven frameworks, reinforcing ETFs’ role as core portfolio building blocks rather than tactical trading vehicles.
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Insights in this article are based on panels and fireside discussions at the ETFs in Depth event held in New York in December 2025.