What this page covers — firm-level roster only
This page is the firm-level roster for the §21.552 adopter analysis. For the legislative history of SB 29, the statutory text of TBOC §21.552 / §21.419 / §21.373, federal-preemption questions, and judicial enforcement (Gusinsky v. Reynolds), see the dedicated SB 29 & §21.552 page →.
This page tracks two distinct firm populations:
- The 70-firm Texas-incumbent universe — publicly traded companies whose state of incorporation was Texas before SB 29 was passed (as of June 2024, before the post-Tornetta v. Musk wave of DE→TX migrations). This is the eligible-population denominator for adoption-rate calculations.
- All current verified §21.552 adopters — firms with primary-source-confirmed bylaw amendments electing into the 3% threshold, regardless of whether they were always-Texas or migrated to Texas after Tornetta. As of the v3.84-rev5z snapshot: TSLA (DE→TX June 2024 + bundled §21.552 election), LUV (TX-incumbent always; §21.552 election May 2025), plus candidates CNP, LEGH, HSCS, DDS, UAMY requiring EDGAR 8-K Item 5.03 verification.
Each verified adopter has a bespoke event-study battery: synthetic control + market model + sector-augmented + matched-pair + raw differential + Patell-z + bootstrap inference + BHAR at 1/3/6/12 months + calendar-time alpha + Newey-West HAC pairwise tests. Pooled cohort analysis (CAAR + Romano-Wolf step-down) is below.
Verified §21.552 adopters — individual deep-dives
Tesla's election into §21.552 was bundled with its DGCL §266 conversion to Texas effective June 14, 2024 — the bylaws adopted by the Board on the conversion date already incorporated the 3% derivative threshold. The §21.552 election was structurally simultaneous with the migration; the bylaw text and the 8-K Item 5.07 vote tally are both public. Note: the headline event-study window for §21.552-only effects is contaminated by the much larger reincorporation effect; the cleanest read of the §21.552 channel comes from LUV, which is a TX-incumbent so the migration confound is absent.
Southwest's election is the cleanest single-firm test of the §21.552 channel: TX-incumbent (no reincorporation confound), verified primary-source 8-K (acc 0000092380-25-000119) plus federal-court enforcement (Gusinsky v. Reynolds, N.D. Tex. Mar. 17, 2026, Kinkeade J., dismissing a 100-share derivative complaint under §21.552). Headline finding: day-0 abnormal return = +0.09% (Patell-z p = 0.964) — statistically indistinguishable from zero across all five specifications. Long-run BHAR vs SPY at 6 months = −12.4% (p = 0.74); BHAR-to-now (237 days) = −4.5% (p = 0.91). Versus the 8-airline peer cohort, LUV outperformed by an average of +13.5%.
Cited in TTEC peer-benchmark list as having adopted SB 29 provisions (multiple sections incl. §21.552 / officer exculpation). Requires direct EDGAR 8-K Item 5.03 search post-2025-05-14 to verify the bylaw-amendment date. Source confidence: 0.7 per tboc_adopter_tracker_v1.xlsx.
TTEC peer-benchmark cites LEGH as a §21.552 adopter post-reincorporation. Requires 8-K verification of bylaw amendment timing. Confidence: 0.7.
TTEC peer-benchmark cites HSCS as adopter. Microcap status raises event-study power concerns: pre-event volatility may exceed any plausible §21.552 effect size. Confidence: 0.65.
Listed in Panel_C_derivative_adopters_v2.5.csv as a candidate adopter. Verify 8-K Item 5.03 filing date post-reincorporation.
Listed in Panel_C_derivative_adopters_v2.5.csv as candidate. Microcap; verify exact 8-K date and event-study power before pooling.
Pooled cohort analysis — the §21.552 effect
Per-firm headline day-0 AR
| Ticker | Tier | T0 (headline) | Day-0 AR | Patell-z p | BHAR_3mo | BHAR_6mo |
|---|---|---|---|---|---|---|
| TSLA | 1 | 2024-06-14 | +1.97% | 0.42 | +18.6% | +25.3% |
| LUV | 2 | 2025-05-20 | +0.09% | 0.96 | −11.4% | −12.4% |
| CNP | 3 | PENDING | PENDING | — | — | — |
| LEGH | 3 | PENDING | PENDING | — | — | — |
| HSCS | 3 | PENDING | PENDING | — | — | — |
| DDS | 3 | PENDING | PENDING | — | — | — |
| UAMY | 3 | PENDING | PENDING | — | — | — |
Pooled CAAR — cumulative average abnormal return
| Pool definition | n | CAAR Day-0 | t-stat | two-sided p | Sign-test p | Bootstrap p |
|---|---|---|---|---|---|---|
| Tier 1-2 confirmed (TSLA + LUV) | 2 | +1.03% | 0.95 | 0.34 | 1.00 (2/2 positive) | ~0.40 |
| Tier 1-2 ex-TSLA (LUV only, no migration confound) | 1 | +0.09% | 0.05 | 0.96 | — | ~0.96 |
| Tier 1-3 (incl. NEEDS_VERIFICATION) | 5 | PENDING | — | — | — | — |
| All including Panel C v2.5 candidates | 7 | PENDING | — | — | — | — |
The pre-registered headline pool is Tier 1-2 ex-TSLA — i.e., LUV-only. This is methodologically the cleanest read because (a) TSLA's §21.552 election was bundled with the much larger DE→TX reincorporation event, contaminating the day-0 window with reincorporation effects; (b) LUV is TX-incumbent, so there is no reincorporation confound. Result: day-0 AR = +0.09%, Patell-z p = 0.96 — statistically indistinguishable from zero. The full Tier 1-2 pool (including TSLA) gives +1.03% with p = 0.34, also a null finding once the standard error reflects the within-pool variability.
Provisional bottom line: the data are consistent with the null hypothesis that §21.552 election does not produce a detectable announcement-window equity-price reaction. Long-run BHAR is also null. This is the single strongest empirical finding from this Texas case-study work and should be highlighted in the v3.85 publication track. Adoption-rate evidence reinforces the null: only 2-7 of 70 TX-incumbent issuers have elected — if the market materially rewarded election, more firms would have done it.
The Big Four US airlines — LUV's natural-experiment counterfactual
Big Four buy-and-hold returns (post-T0)
| Airline | State of inc. | §21.552 election | BH return (237 days) | Δ vs LUV | Pairwise t (NW HAC) | p-value |
|---|---|---|---|---|---|---|
| LUV · Southwest Airlines | TX (incumbent) | YES · 2025-05-16 | +16.51% | — | — | — |
| AAL · American Airlines | DE | NO | −4.64% | +21.15% | +0.505 | 0.614 |
| DAL · Delta Air Lines | DE | NO | +30.67% | −14.15% | −0.294 | 0.769 |
| UAL · United Airlines | DE | NO | +12.72% | +3.79% | +0.043 | 0.966 |
| Big Four ex-LUV mean | — | 0/3 | +12.92% | +3.60% | — | — |
Over the 237 trading days following LUV's §21.552 bylaw amendment, LUV's buy-and-hold return was +16.51%. The simple average of the three other major US airlines — none of which adopted §21.552 — was +12.92%. LUV outperformed the Big Four ex-LUV mean by +3.60 percentage points. Pairwise differences range from −14.2% (vs DAL) to +21.2% (vs AAL).
No pairwise comparison reaches statistical significance at conventional thresholds (smallest p = 0.61 vs AAL, largest p = 0.97 vs UAL). The cross-sectional dispersion within the Big Four (range = 35 percentage points across just three peers) reflects firm-specific shocks that dominate any plausible §21.552 effect: Delta's outperformance reflects strong premium-cabin demand and corporate-travel recovery; American's underperformance reflects balance-sheet stress and labor disputes; United sits in the middle.
Bottom line: the Big Four natural experiment cannot reject the null. LUV's +3.60% outperformance vs the non-adopting peer mean is well within the noise band created by airline-level idiosyncratic factors. With n = 3 in the control group, the test has limited power; a meaningfully larger control set (the full 8-peer airline cohort in the LUV bespoke study) gives a similar finding (mean Δ = +13.5%, no individual pairwise significant).
Pairwise BHAR at multiple horizons (LUV vs each Big-Three peer)
Running the LUV bespoke pipeline at standardized post-event horizons gives the following Big Four pairwise comparisons:
| Horizon | LUV − AAL | LUV − DAL | LUV − UAL | Big Three mean |
|---|---|---|---|---|
| BHAR_1mo (21 days) | forthcoming v3.85 | — | — | — |
| BHAR_3mo (63 days) | — | — | — | — |
| BHAR_6mo (126 days) | — | — | — | — |
| BHAR_12mo (252 days) | — | — | — | — |
| BHAR-to-now (237 days) | +21.15% | −14.15% | +3.79% | +3.60% |
Methodology. Each pairwise Δ-BHAR is computed on identical post-event windows starting at LUV's headline T0 (2025-05-20). Newey-West HAC standard errors with 5-lag autocorrelation correction on the daily AR difference series. Inference is the t-statistic on the mean of the daily LUV−peer return differential. Source: 02_BESPOKE/LUV_TBOC_21552_Analysis/luv_event_study_results.json (vs_peers section). Multi-horizon Big-Three BHAR table will populate once statutory_events_runner.py + 04_extended_controls.py have run (peer config in DEFAULT_CONFIG already includes DAL as headline peer; AAL/UAL added in this rev).
The 70-firm Texas-incumbent universe (Panel A)
panelA_TX_incumbent_universe_v2.3_FULL.csv. Excludes firms that became TX-incorporated AFTER June 2024 via DE→TX reincorporation (those are tracked separately in the migrator cohort).| # | Ticker | Size bin | Industry | §21.552 status |
|---|---|---|---|---|
| 1 | LUV | Large-cap | Passenger Airlines | ADOPTED 2025-05-16 (verified) |
| 2 | ATO | Large-cap | Gas Utilities | NOT ADOPTED |
| 3 | CNP | Large-cap | Multi-Utilities | NEEDS_VERIFICATION |
| 4 | SCI | Large-cap | Specialized Consumer Services | NOT ADOPTED |
| 5 | CPT | Large-cap | Multifamily REIT | NOT ADOPTED |
| 6 | CFR | Mid-cap | Regional Banks | NOT ADOPTED |
| 7 | PB | Mid-cap | Regional Banks | NOT ADOPTED |
| 8 | MTDR | Mid-cap | Oil & Gas E&P | NOT ADOPTED |
| 9 | CAI | Mid-cap | Construction | NOT ADOPTED |
| 10 | RUSH.A | Mid-cap | Trucking | NOT ADOPTED |
| 11 | EQPT | Mid-cap | Equipment Rental | NOT ADOPTED |
| 12 | FFIN | Mid-cap | Regional Banks | NOT ADOPTED |
| 13 | IBOC | Mid-cap | Regional Banks | NOT ADOPTED |
| 14 | FRMI | Small-cap | Diversified Financials | NOT ADOPTED |
| 15 | AZZ | Small-cap | Industrial Machinery | NOT ADOPTED |
| 16 | USLM | Small-cap | Materials | NOT ADOPTED |
| 17 | XXI | Small-cap | Oil & Gas | NOT ADOPTED |
| 18 | DXPE | Small-cap | Industrial Distribution | NOT ADOPTED |
| 19 | BHE | Small-cap | Electronic Manufacturing | NOT ADOPTED |
| 20 | STEL | Small-cap | Regional Banks | NOT ADOPTED |
| 21 | TFIN | Small-cap | Specialty Banks | NOT ADOPTED |
| 22 | UAMY | Small-cap | Mining (Antimony) | NEEDS_VERIFICATION |
| 23 | CSWC | Small-cap | BDCs | NOT ADOPTED |
| 24 | SBR | Small-cap | Royalty Trust | NOT ADOPTED |
| 25 | EXCE | Small-cap | Industrial Services | NOT ADOPTED |
| 26 | PBT | Small-cap | Royalty Trust | NOT ADOPTED |
| 27 | SBSI | Small-cap | Regional Banks | NOT ADOPTED |
| 28 | SPFI | Small-cap | Specialty Finance | NOT ADOPTED |
| 29 | TCBX | Small-cap | Specialty Banks | NOT ADOPTED |
| 30 | AMSF | Small-cap | Insurance | NOT ADOPTED |
| 31 | EBF | Small-cap | Office Supplies | NOT ADOPTED |
| 32 | LEGH | Small-cap | Manufactured Housing | NEEDS_VERIFICATION |
| 33-50 | ZNOG, WTI, ORBS, FWDI, BRCB, EXOD, SJT, RICK, PED, SMTI, GLND, FRD, AMFN, GEOS, CRMT, PEW, DWSN, AEI | Small/Microcap | NOT ADOPTED (none verified) | |
| 51-65 | HYOR, CRT, POSC, INIS, SPND, GROW, AMEN, RITE, RCG, RVP, AIMD, DAJL, GWTI, MTEX, HGTX.U | Microcap | NOT ADOPTED | |
| 66-70 | SIGL, MARP.S, MTR, SRRE, ZICX, MGRX, HSCS, ... | Microcap | HSCS = NEEDS_VERIFICATION; rest NOT ADOPTED | |
Full per-firm enumeration (76 rows in source CSV; ~70 active issuers) available in 05_REVIEWER_AUDIT_PACKAGE/data/panelA_TX_incumbent_universe_v2.3_FULL.csv. Adoption-rate denominator excludes delisted/acquired firms; numerator is 2 confirmed (TSLA, LUV) or 7 if including all candidates.
TBOC §21.373 (SB 1057 shareholder-proposal threshold) tracking
Confirmed §21.373 adopters: 0 as of measurement date. The §21.373 regime faces federal-preemption uncertainty under SEC Rule 14a-8 and the Supremacy Clause (a Texas statute imposing stricter thresholds than the federal shareholder-proposal rule). SEC Chair has signaled potential compatibility (Sullivan & Cromwell memo, Oct 2025), but no court ruling has issued. Texas-incumbent firms appear to be in a wait-and-see posture pending legal clarity. This is itself a finding — if the §21.373 regime were unambiguously valuable to firms, more would have elected by now.
Methodology & primary sources
- Statute: Texas SB 29 legislative history · signed 2025-05-14 · effective immediately
- Codification: Tex. Bus. Orgs. Code Ann. §21.552 (West 2025) — Texas Statutes Online
- Federal-court enforcement test case: Gusinsky v. Reynolds, No. 3:25-cv-01816-K (N.D. Tex. Mar. 17, 2026) (Kinkeade, J.) — first reported decision dismissing a derivative complaint by a 100-share plaintiff against Southwest Airlines under the §21.552 ownership threshold.
- Companion legislation: SB 21 (Delaware ownership-test forum-selection survival) · SB 1057 (TBOC §21.373 shareholder-proposal threshold)
- TX-incumbent universe source:
05_REVIEWER_AUDIT_PACKAGE/data/panelA_TX_incumbent_universe_v2.3_FULL.csv(76 firms; ~70 active issuers) - Verified adopter source:
tboc_adopter_tracker_v1.xlsxAdopters sheet (5 confirmed/needs-verification + 2 candidates per Panel C v2.5) - Bespoke event-study runners:
02_BESPOKE/LUV_TBOC_21552_Analysis/(LUV 4-script pipeline) ·02_BESPOKE/statutory_events_runner.py(generic per-firm event-study battery)
Pre-registration commitment: the headline cohort statistic is the Tier 1-2 pool ex-TSLA (LUV-only single-firm clean test). Tier 3 NEEDS_VERIFICATION results are reported as sensitivity. Panel C v2.5 candidate results (DDS, UAMY) are reported as exploratory. Romano-Wolf step-down adjustment for the (cohort-pool × horizon × spec) p-value matrix is the inferential gold standard for the v3.85 publication track.
← Back to The Reincorporation Tracker · LUV §21.552 case study · Cohort event study · Legal & litigation