Did MSFT's record Jul 30 earnings pop outpace fellow hyperscalers, or did the whole group re-rate?

Treated: MSFT. Donors: GOOGL, META, AMZN (fellow Mag-7 hyperscalers, same donor logic as googl_capex_guidance). Hand-picked, not algorithmic. Treatment date is MSFT's Jul 30 after-close report: revenue +18% YoY to $90B, net income +31%, and guidance for ~45% constant-currency Azure growth (vs. a 40.92% estimate); the stock closed up about 16%, adding nearly $450B in market value, the largest single-day market-cap gain on record for any company. This is the mirror case of googl_capex_guidance: that one tested whether GOOGL's post-guidance selloff eight days earlier (Jul 22) was company-specific or a shared re-pricing; this tests the same question on the opposite signal (a beat instead of a miss), in the same hyperscaler group within the same two-week window.

Actual vs. synthetic counterfactual

Actual Synthetic (counterfactual)

Fit quality

Fit-window RMSE3.9427

RMSE ÷ fit-window std dev0.83×

Fit-window days125

Confound-window mean gapn/a (fit-end = treatment date)

Post-period mean gap+21.98

Placebo test: same method run on every unit, treated one highlighted

Unit	Mean post-period gap	Max abs. gap
META	-29.77%	39.29%
MSFT (treated)	+21.98%	29.09%
AMZN	+6.44%	11.81%
GOOGL	-6.39%	11.93%

Verdict

Caution on fit quality: the fit-window RMSE is 0.83× this unit's own fit-window standard deviation, a loose fit. Treat the gap below as suggestive at best, not a clean read.

MSFT's post-period gap ranks #2 of 4 units by absolute size in the placebo test (larger rank = more likely a real, unit-specific effect rather than noise the method would produce for any random unit).

Read: this does NOT look like a clearly unit-specific effect; other units in the placebo test show gaps of similar or larger size, so this could just be estimation noise rather than a real, distinct move.