• Telecoms crash — Wikipedia (2024)

Aggregate US telecom-equipment capital investment 1996-2001 — approximately USD 500 billion in nominal dollars, financed largely with debt. The buildout that preceded the 2001 telecom bust.

• Bloomberg Intelligence — Generative AI to become a $1.3 trillion market by 2032 (2023)

Estimated 2025 global generative-AI software and services revenue (approximately USD 50 billion), per Bloomberg Intelligence's market sizing. Capex-to-revenue ratio is one of the most cited single bubble indicators.

• The Planetary Society — How much did the Apollo program cost? (2024)

Total cumulative cost of the Apollo program (1961-1973), inflation-adjusted to 2024 USD: approximately USD 280 billion. Covers Mercury and Gemini predecessor programs, the Saturn V launch system, and all Apollo missions through Apollo 17.

• Brookings Institution — The Costs of the Manhattan Project (Atomic Audit, Stephen I. Schwartz) (1998)

Total cost of the Manhattan Project (1942-1946), USD 1.9 billion nominal, inflation-adjusted to approximately USD 30 billion in 2024 USD per Brookings' Atomic Audit (Schwartz, 1998).

• Nature Food / IFPRI — Investment needs to end hunger by 2030 (2020)

Average additional annual public expenditure (approximately USD 33 billion) required from donors and low/middle-income governments through 2030 to end hunger (SDG 2), per Ceres2030 / IFPRI models published in Nature Food.

• World Bank — The Costs of Meeting the 2030 SDG Targets on Drinking Water, Sanitation, and Hygiene (2016)

Annual capital investment of approximately USD 114 billion needed through 2030 to achieve universal safely managed drinking water, per the World Bank's SDG 6 costing study (Hutton & Varughese 2016).

• The Lancet Commission on Malaria Eradication (2019)

Total cumulative additional global investment required to eradicate malaria by 2030 (approximately USD 90-120 billion), per the Lancet Commission's modelled additional funding on top of current spending.

• Princeton REPEAT Project — Net-Zero America (2024)

Estimated annual capital investment required to modernise the US power grid (transmission upgrades, distribution hardening, interconnection-queue clearing) — approximately USD 167 billion per year over 30 years toward a net-zero-aligned grid, per Princeton REPEAT and DOE Grid Deployment Office estimates.