Active ETF
An active ETF is an exchange-traded fund in which a portfolio manager makes discretionary or systematic decisions about which securities to hold and in what proportions, rather than mechanically tracking a predetermined index, combining the tax efficiency and intraday tradability of the ETF structure with the flexibility of active portfolio management.
For most of the ETF industry's history, the dominant model was passive: an ETF tracked an index, and the manager's role was purely operational — replicating the index with minimal tracking error. The SEC's approval framework long required daily portfolio disclosure, which deterred active managers from using the ETF structure because revealing their holdings daily would allow competitors to front-run their trades. Regulatory changes, including the SEC's 2019 ETF Rule and subsequent approval of non-transparent active ETF structures, removed this barrier and opened the ETF vehicle to mainstream active management.
Active ETFs come in two disclosure models. Fully transparent active ETFs disclose their complete portfolio daily, just as passive index ETFs do. This model is used by managers whose strategies are not easily front-run — for example, fixed income active ETFs, where individual bond positions are less susceptible to front-running than equity positions. Semi-transparent or non-transparent active ETFs disclose a proxy portfolio to authorized participants rather than the full holdings, relying on approved structures such as the NYSE-developed Active Proxy structure and the Precidian ActiveShares model to maintain arbitrage efficiency without revealing proprietary positions.
ARK Invest pioneered high-profile fully transparent active equity ETFs in the U.S. market, with ARK Innovation ETF (ARKK) accumulating over $27 billion in assets at its peak in early 2021 before experiencing a substantial drawdown. Traditional active fund managers including T. Rowe Price, Fidelity, Dimensional Fund Advisors, and J.P. Morgan Asset Management have launched active ETFs, many converting existing mutual fund strategies or launching parallel ETF share classes. Dimensional, which manages systematic factor-tilted portfolios, converted several large mutual funds into ETFs in 2021, citing tax efficiency and structural cost advantages.
The tax efficiency argument for active ETFs relative to active mutual funds is meaningful. The in-kind creation and redemption mechanism of the ETF structure allows the fund to offload low-cost-basis securities to redeeming authorized participants rather than selling them, avoiding the realization of capital gains inside the fund. Active mutual funds, by contrast, must sell securities to meet cash redemptions, often triggering capital gains distributions that flow through to all remaining shareholders. This structural advantage has been documented empirically and represents a genuine benefit of the ETF wrapper for taxable accounts.
Expense ratios for active ETFs are generally higher than for passive index ETFs but often lower than comparable active mutual funds, particularly after class-level fee differences are accounted for. Evaluating an active ETF requires assessing the manager's investment process, the basis for expected outperformance, the historical live performance record, and whether the ETF structure preserves the full integrity of the strategy at scale.