Shrinking equity supply has kept the current bull market alive as fewer shares list and more delist. Institutional scarred by the early‑2000s bear market favoured buybacks and debt‑financed takeovers, while private equity pushed companies private. IPOs, secondaries and equity‑financed M&A fell to a trickle, cementing a four‑year “de‑equitisation” trend in the US and UK.

That balance now cracks as the AI boom forces capex‑heavy spending. Alphabet, Amazon, Meta and Microsoft plan to invest roughly $725 bn this year, prompting Meta and Alphabet to suspend share repurchases after recycling $92 bn in 2024. By contrast, Apple announced a $100 bn buyback slated for 2026, a modest move against a $4.3 tn market cap.

Private AI firms have already raised $152 bn in 2026, and entities such as OpenAI, Anthropic and SpaceX are eyeing IPOs that could total $4 tn in valuation. Even a fractional public float would add roughly 6 % to US equity supply, a level not seen since the late‑1990s bubble, pressuring prices as investors seek exits.

With buyback pipelines drying and AI‑driven capex absorbing cash, the protective “put” that has underpinned valuations is eroding. Market participants should expect tighter share supply and potentially higher price volatility as the private‑to‑public pipeline materialises, marking the end of the de‑equitisation era for investors in the near term.