docs(sec): post-reparse verification and cutover recommendation

Closes the parity investigation: prod reparse runs 6+7 reconciled against the
dry run, the collision check that caught the BEN regression (and its residue --
36 historical 53-week-drift rows, deliberately left), and the 2026-07-24 parity
report diffed against the 2026-07-23 baseline. Candidate coverage 482 -> 504 of
511 with the gap fully explained (PSKY/Q new registrants, FITB guard-tripped
with no revenue), agreement unchanged where both sides exist, and the remaining
deltas are documented definition differences. Includes the after-report and a
correction to the seventh pass (FITB loses its score, not just one input).
Recommends approving the A5 cutover with KLAC as the one carried caveat.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

reports/fundamentals-parity-20260723-findings.md

@@ -853,3 +853,73 @@ track the parser's `SnapshotRow`, and only one of them is now enforced by a test
 
 PSKY and Q need nothing — they are new registrants without enough filing history, which is
 correct behaviour.
+
+---
+
+# Closing — post-reparse verification (2026-07-24)
+
+## Production reparse
+
+Two apply runs against prod (`scripts/reparse_fundamentals.py --apply`):
+
+- **Run 6** (all fixes through the seventh pass): 262 inserted, 28,664 rewritten —
+  99.4% of which was backfilling the new `weighted_avg_diluted_shares` column; the
+  behavioural churn matched the dry run exactly. The five duration facts clustering at
+  190–234 changed rows each is the 4-4-5 Q3 recovery signature. `accepted_at` changed on
+  only 76 rows (0.25%), confirming the tz-comparison fix works against real Postgres.
+- **Run 7** (after the fiscal-year-end fix below): 3 inserted, 322 rewritten — BEN, DELL,
+  and boundary-year relabels for 53-week filers whose derived MMDD shifted a few days.
+
+`cik_updates: 1` on run 6 was the XOM pin taking effect; XOM now has 68 snapshot rows,
+latest period end 2026-03-31.
+
+## Regression caught by the collision check — and its fix
+
+The before/after key-collision query (~130 rows max 6 → 44 rows all 2) surfaced one real
+regression: **BEN**. `submissions.fiscalYearEnd` declares `1231` while every Franklin
+Resources 10-K ends 09-30, so `_period_identity` — which trusted the declared value — put
+BEN's real fiscal Q1 zero days from the claimed year end (no band matched) and labelled its
+fiscal Q2 as Q1. The collision discarded a period and BEN lost TTM EPS and revenue growth it
+had before the branch. Fixed in `3d42ca7`: `resolve_fiscal_year_end()` prefers the issuer's
+own most recent 10-K reportDate (which *is* the fiscal year end by definition) and treats
+the declared field as fallback. Full-universe scan: 2 of 506 issuers mis-declare (BEN 91d,
+DELL 29d); both now derive correctly (BEN rg 3.8243 vs legacy 3.82; DELL 38.5735 vs 38.57).
+
+Residual collisions after run 7: 36 rows, all count-2, **latest year 2023** — the 53-week
+drift class (AVY/CDNS/RVTY/JNJ/TDY/DPZ at 5–6-year intervals). Newest-wins degrades one
+historical FY row; no current period is affected. Left alone deliberately: eliminating them
+means modelling each filer's actual 52/53-week calendar per year, for rows feeding no
+current metric.
+
+## The verdict: 2026-07-24 parity report vs the 2026-07-23 baseline
+
+| metric | baseline | after | |
+|---|---|---|---|
+| candidate scored | 482 | **504** | legacy scores 507; gap = PSKY, Q (new registrants) + FITB |
+| revenue_growth candidate available | 442 | **489** | banks, REITs, 4-4-5 recovered |
+| pe_ratio candidate available | 432 | **452** | net of the split-guard nulls |
+| revenue_growth median abs delta | 0.0038 | **0.0038** | 47 names added at unchanged agreement |
+| pe_ratio median / p95 abs delta | 0.5883 / 7.73 | **0.5576 / 6.03** | corrupted outliers gone |
+
+Revenue `material_differences` rose 84 → 96: the newly compared names include the cases
+where **legacy is the wrong side** (JPM 108.98% vs 3.34%, PPL −58.81% vs 8.34%, FCX −24.23%
+vs +5.44%). Material is symmetric; these flag the provider being corrected.
+
+The split guard is visible in the report: BKNG (1.10), COF, TPL, AMCR, WAT all null P/E now.
+**KLAC (6.19) is the one known-wrong value left** — the post-filing split documented as
+unfixable without a corporate-actions source.
+
+**Correction to the seventh pass:** the claim that guard-tripped issuers "keep their
+fundamental score, losing one of three inputs" fails for **FITB**, the one name that also
+lacks revenue growth (its recent filings tag only ASC-606 fee-income fragments, then nothing)
+— nulling its contaminated P/E (Comerica merger, 661M → 902M shares) drops it to one metric
+and no score. Accepted: the composite renormalises, and legacy's 58% "revenue growth" for a
+bank was itself junk.
+
+## Recommendation
+
+The A5 gate evidence now supports approving the cutover: coverage within 3 of legacy with
+every gap explained, agreement essentially exact where both sides exist, every corrupted
+value either fixed or deliberately nulled with a caveat, and the remaining score deltas are
+documented definition differences — called out, not averaged away, as the plan requires.
+Carry KLAC as the one known caveat in the approval note.