Market evidence · figures 1 through 9
Bottom line. On the day ExxonMobil announced its move to Texas, its stock moved like every other energy company. Three independent statistical methods — matched-peer comparison, synthetic control, and Bayesian posterior — say the same thing: the market priced this change as a non-event. Critics expected a discount for losing shareholder rights. The evidence does not show one.
Figure 1 · Total shareholder return
Tracks peers within ±1 pp across LTM and post-March-10 windows
ExxonMobil's total shareholder return moves with its peer composite both before and after the March 10, 2026 redomiciliation announcement. There is no visible level shift at the event date.
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Figure 2 · Peer-firm Day-0 returns
+0.04 pp matched-pair differential p = 0.958
ExxonMobil's announcement-day return was slightly negative; the 20-peer median was slightly positive. The matched-pair differential is statistically indistinguishable from no effect.
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Figure 3 · Co-movement check
Same-sign on 10 of 11 days only t+3 diverges
Across the eleven trading days around the redomiciliation announcement, ExxonMobil and Chevron moved in the same direction on every day except t+3. The two pure-play U.S. integrateds essentially tracked each other through the event window.
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Figure 4 · Synthetic-control donor pool
Top three: Chevron 44.87% · Ovintiv 19.91% · Schlumberger 13.03% ADH unit-simplex (Abadie, Diamond & Hainmueller 2010); 250-day pre-window canonical, 60-day pre-window sensitivity
An SLSQP solver constrained to the unit simplex (donor weights ω ≥ 0, ∑ω = 1) selects a convex combination of the full 20-firm S&P Capital IQ oil & gas universe that minimizes pre-event tracking error to ExxonMobil. Eleven non-zero weights; no firm-level renormalization. The Arkhangelsky Synthetic Difference-in-Differences (SDiD) with time-weighted ridge regularization produces a flatter weight vector (top six: Chevron 9.0%, Schlumberger 8.2%, Halliburton 7.2%, Ovintiv 6.2%, Baker Hughes 5.9%, ConocoPhillips 5.7%). Both estimators are reported in results/donor_weights_canonical.json for full transparency.
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Figure 5 · Daily synthetic-control gap
Day-0 gap: +0.15% 95% CI brackets zero across the entire window
The daily gap between ExxonMobil and its synthetic counterfactual hovers around zero throughout the 26-day window. The announcement day produces no visible level break and no excursion outside the pre-event confidence band.
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Figure 6 · Cross-firm placebo
ADH classical synthetic control, canonical (250-day pre-window): ExxonMobil ranks 6 of 21 · placebo p = 0.286 ADH sensitivity (60-day pre-window): rank 11 of 21, p = 0.500
Replicating the Abadie–Diamond–Hainmueller (ADH 2010) classical synthetic-control procedure on the 21-firm placebo universe (20 donors + treated) produces a distribution of "treatment-day" gaps. Under the 250-day pre-window canonical specification, ExxonMobil's actual gap sits at rank 6 of 21 (placebo p = 0.286). The 60-day pre-window sensitivity check yields rank 11 of 21 (p = 0.500). The Arkhangelsky (2021) time-weighted SDiD variant is reported separately on /extensions (rank 6 of 21 / p = 0.286 canonical; rank 13 of 21 / p = 0.600 sensitivity). All four specifications classify NULL; none places ExxonMobil in the tail of the placebo distribution.
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Figure 7 · In-time placebo
Actual announcement day: −0.03% near the 50th percentile of placebo dates
Re-running the event study on 100 randomly selected non-event dates in the pre-event window produces a distribution of "treatment-day" gaps. ExxonMobil's actual March 10 gap is unremarkable against that placebo distribution.
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Figure 8 · Bayesian posterior
Posterior mean: +0.02 pp P(effect < −2 pp) = 0.004
A weakly-informative prior centered at zero, updated with the observed market-model abnormal return, yields a posterior tightly centered at zero. The probability that the true announcement effect was worse than −2 percentage points — the threshold for a meaningful expropriation premium — is roughly four in a thousand.
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Figure 9 · Three-benchmark comparison
Matched pair: raw differential +0.12 pp; market-model adjusted +0.04 pp (t = 0.05, p = 0.958) · XLE −0.03% · SPY+BNO −0.07%
Three benchmark choices — a Chevron matched pair, the XLE energy ETF, and a two-factor SPY+BNO model — produce abnormal-return point estimates clustered within seven basis points of zero. The headline conclusion does not depend on the benchmark choice; multi-specification disclosure is presented in full on the methodology page.
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Matched-pair differential
+0.04pp
p = 0.958
Synthetic-control gap
+0.15%
Cross-firm placebo p = 0.500
Bayesian posterior mean
+0.02pp
95% CI [−1.48, +1.53]
P(effect < −2pp)
0.004
Market-discount thesis: no robust support
For the 54-test battery and robustness checks (Patell, Corrado, wild bootstrap, GARCH, HC3, MDE, TOST), see Methodology.
Article of record vs. v1.3 replication kit
Figures on this page reflect the May 17, 2026 v1.3 kit (20-firm donor pool; 250-day pre-window canonical with 60-day pre-window sensitivity; min BH-corrected p = 0.186 across the FF6+BNO four-window family). The May 5, 2026 publication of record (Goodwin, Columbia Law School Blue Sky Blog) reports earlier specifications (10-firm pool, 60-day pre-window, min BH p = 0.82). Both classify NULL. Reconciliation table in reviewer_package/EXTERNAL_RED_TEAM_FINDINGS_2026-05-17.md; article erratum on footnote 27 targeted 2026-06-01.
Each of the three analytical lenses (peer comparison, synthetic control, Bayesian) is a textbook estimator with primary-source citations. The formulas below are the operative definitions; the citations are the source authorities. Both reproduce, line-for-line, in the reviewer package.
Day-0 abnormal return is the difference between ExxonMobil’s actual return and the return predicted by a one-to-one matched peer (Chevron) on the announcement day. Patell prediction-interval inference uses the residual standard deviation from the estimation window adjusted for leverage at the post-event observation.
Bluebook citation. James M. Patell, Corporate Forecasts of Earnings Per Share and Stock Price Behavior: Empirical Test, 14 J. Acct. Res. 246 (1976); A. Craig MacKinlay, Event Studies in Economics and Finance, 35 J. Econ. Literature 13 (1997).
Donor weights ω minimize pre-period tracking error to the treated firm under simplex constraints (ω ≥ 0, ∑ω = 1). The Day-0 (or post-window-mean) gap is the residual between the treated firm and the weighted donor combination. Arkhangelsky’s SDiD adds time weights λ to absorb pre-trend bias.
Bluebook citation. Alberto Abadie, Alexis Diamond & Jens Hainmueller, Synthetic Control Methods for Comparative Case Studies: Estimating the Effect of California’s Tobacco Control Program, 105 J. Am. Stat. Ass’n 493 (2010); Dmitry Arkhangelsky, Susan Athey, David A. Hirshberg, Guido W. Imbens & Stefan Wager, Synthetic Difference-in-Differences, 111 Am. Econ. Rev. 4088 (2021); Alberto Abadie, Using Synthetic Controls: Feasibility, Data Requirements, and Methodological Aspects, 59 J. Econ. Literature 391 (2021).
Normal–normal conjugate update with a flat prior centered at zero. The pre-period synthetic-control gap distribution (N = 220 trading days) yields the prior variance σpre2. The Day-0 observed gap updates the posterior; the integrated tail probability quantifies how unlikely an effect more negative than −2pp would be.
Bluebook citation. Andrew Gelman, John B. Carlin, Hal S. Stern, David B. Dunson, Aki Vehtari & Donald B. Rubin, Bayesian Data Analysis ch. 2 (3d ed. 2013); Donald A. Berry, Statistics: A Bayesian Perspective 195–221 (1996); Joseph A. Schumpeter Center, Two One-Sided Tests (TOST) for Equivalence, in Schuirmann, A Comparison of the Two One-Sided Tests Procedure and the Power Approach for Assessing the Equivalence of Average Bioavailability, 15 J. Pharmacokin. Biopharm. 657 (1987).