Could mega IPOs end the 'equity shrinkage' era?

Bank of America Research warns that a long-running tailwind for U.S. equities — a two-decade shrinkage in the supply of publicly traded stock driven by buybacks and take-privates — may be reversing as mega‑IPOs loom. That reversal could materially alter market dynamics that have supported indexes like the S&P 500, removing a structural supply constraint and potentially muting future price appreciation or volatility behavior. The article highlights ETFs tied to the market (SPY, DIA, QQQ) as touchpoints for investors; the immediate market action shown in the piece (SPY/DIA/QQQ gains) reflects ongoing market sensitivity to such supply-side shifts. Overall, the note represents an institutional outlook that increased new listings could change liquidity and valuation trends, creating both opportunities and risks for index and ETF investors.