Did Micron's Jul 1 'Meta Compute' selloff break it from fellow chip suppliers, or hit the whole group?

Treated: MU. Donors: AMD, NVDA, INTC (AI/GPU-chip suppliers facing the same demand-destruction read). Hand-picked, not algorithmic. Treatment date is 2026-07-01: Meta announced 'Meta Compute,' a plan to resell its own excess AI infrastructure capacity, which the market read as evidence hyperscaler GPU demand may be peaking rather than perpetually scarce. Chip suppliers sold off hard the same day (MU -10.6%, AMD -6.9%, NVDA -1.25%, the Philadelphia Semiconductor Index down over 10% across the next two sessions), even as META itself rose about 9% on its own announcement: a genuine divergence between the company making the move and the suppliers reading it as bad news. This is a different mechanism from sndk_supply_glut_fear (that one was about NAND/DRAM oversupply from Samsung/SK Hynix; this one is about AI-chip demand destruction from a hyperscaler reselling capacity instead of buying more). Tests whether MU's outsized drop was company-specific or the whole chip-supplier group re-priced together on the same news.