John O’Connell was recently published in Kiplinger, the second in his series on AI concentration risk, arguing that AI isn’t an industry but a six-layer supply chain, running from chip design and fabrication through data movement, data-center construction, the hyperscalers writing the checks, and the software layer that has to monetize it all. His point is that owning Nvidia, AMD, Broadcom, and a hyperscaler across three different funds feels like diversification, but it’s really one bet sized three times over, since every layer depends on the same four customers spending $700B-plus in 2026 at a pace none has sustained before. His advice is to map the top 10 holdings of every growth fund you own to a layer, and ask what happens to each if hyperscaler capex merely slows rather than reverses, since a drop from 70% to 20% growth is still a down year for every layer beneath it.