Steering a Ship in Illiquid Waters: Active Management of Passive Funds
Exchange-traded funds (ETFs) are typically viewed as passive index trackers. In contrast, we show that corporate bond ETFs actively manage their portfolios, trading off index tracking against liquidity transformation. In our model, ETFs optimally choose creation and redemption baskets that include cash and only a subset of index assets, especially if those assets are illiquid. Our evidence supports the model. We find that ETFs dynamically adjust their baskets to correct portfolio imbalances while facilitating ETF arbitrage. Basket inclusion improves bond liquidity in general, but worsens it in periods of large imbalance between creations and redemptions, such as the COVID-19 crisis.
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Copy CitationNaz Koont, Yiming Ma, Lubos Pastor, and Yao Zeng, "Steering a Ship in Illiquid Waters: Active Management of Passive Funds," NBER Working Paper 30039 (2022), https://doi.org/10.3386/w30039.Download Citation
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Published Versions
Naz Koont & Yiming Ma & Lubos Pastor & Yao Zeng & Clemens Sialm, 2025. "Steering a Ship in Illiquid Waters: Active Management of Passive Funds," The Review of Financial Studies, vol 38(10), pages 2887-2935.
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