Section 351 ETF

ETFs Cross the Threshold From Wrapper to Backbone

State Street’s 2026 Global ETF Outlook makes the case that ETFs have outgrown their original identity. With global ETF assets approaching $22 trillion, the vehicle once described as a disruptive wrapper now functions as core market infrastructure.

Three global trends shaping the year ahead for ETFs.

First, active ETFs continue to pull capital across regions. Active fixed income and derivative income strategies like covered calls and defined outcome funds are driving most of the flow. The fixed income shift is striking. In 2022, active strategies captured 6 percent of total fixed income ETF inflows. By 2025, that figure reached 42 percent.

Second, the wrapper is absorbing strategies that used to live behind institutional walls. Multi coin crypto, pre IPO exposure, and private market style ETFs are pushing into the liquid open ended format. These strategies carry capacity constraints. Issuers will need to manage liquidity, scaling, and investor education as the lines between public and private exposure continue to blur.

Third, growth will hinge on operational plumbing more than ticker launches. Three structural shifts stand out.

Mutual fund to ETF conversions crossed 170 funds and over $125 billion in assets, with more than 50 conversions in 2025 alone. Half of surveyed issuers plan to convert at least one fund over the next twelve months.

Section 351 exchanges are gaining traction as wealth managers look for ways to contribute appreciated securities into diversified ETFs without triggering capital gains. The mechanism functions as an efficient external seeding channel and a tax aware path for advisors managing concentrated client positions.

State Street's 2026 ETF outlook. Active flows, mutual fund conversions, and Section 351 exchanges are reshaping the $22 trillion market

ETF share classes within existing mutual fund structures are expected to launch in early 2026 following regulatory relief. The rollout may be slow given operational complexity and differing economics across gatekeepers, but the structure preserves historical track records and opens a long runway for legacy managers.

The regional picture varies. North America entered 2026 on back to back years of $1 trillion plus US inflows and a record $100 billion in Canada. ETFs now represent roughly 30 percent of Millennial portfolios. Europe is on pace to top $4 trillion in AUM by year end, driven by retail distribution and retirement platforms. Asia Pacific growth is uneven, shaped by local tax programs, leverage rules, and policy backed thematic demand.

The conclusion is direct. Success in 2026 will depend on execution over expansion. The firms that win will be those that can operate at scale, manage the backend complexity of dual structures, and stay structurally resilient through volatility.

Source: State Street, 2026 Global ETF Outlook: From Wrapper to Backbone