# Do auditor changes, director resignations and defaults predict stock returns in India?

> On 4.5 years of NSE Reg-30 announcements, no red-flag category predicted returns once compared with same-day peers.

Published 2026-10-30 by TRINETRA.


**Date:** 2026-10-30
**Scripts:** `engine/scripts/bench_redflag_events.py`, `engine/scripts/bench_redflag_robust.py`
**Data:** NSE corporate announcements 2022-01 → 2026-07, 55 monthly pulls, cached in
`data/audit/redflag_announcements.json`. Results in `BENCH_redflag_events.json` and
`BENCH_redflag_robust.json`.
**Idea source:** trader-skill `trader-news`, which ranks 8-K items 4.01 (auditor change),
4.02 (non-reliance), 5.02 (officer change) and 2.04 (debt acceleration) as IMPORTANT.

## Verdict: no category predicts forward returns. One false positive was caught and retracted.

## Stage 1: same-stock placebo, Benjamini-Hochberg over 18 cells

| category | priced events | 20d median excess | 60d | 120d | best q |
|---|---|---|---|---|---|
| Change in Auditors | 1,013 | −0.04 (null −0.19) | −0.19 (+0.36) | **−2.10 (+1.56)** | **0.018** |
| Independent director resigned | 396 | +0.65 | +1.01 | +3.89 | 0.49 |
| Debt default | 106 | −1.73 | +5.91 | +14.24 | 0.49 |
| Fraud/default/arrest | 23 | −0.46 | −4.01 | +3.01 | 0.82 |
| Insolvency (CIRP) | 20 | −0.67 | +7.62 | +11.24 | 0.49 |
| Rating upgrade | 42 | −1.79 | −2.90 | +1.45 | 0.49 |

The rating-downgrade cell had 3 priced events, too few to test.

## Stage 2: the one survivor fails a date-matched control

The stage-1 placebo used the same stock at random dates. Auditor appointments cluster at AGM
season, so it never controlled for **when** events happen. Stage 2 compares each event against
the median of every other priced stock entered on the same session, with a sign-flip null:

| auditor change | n | median vs same-day peers | p | by year (120d) |
|---|---|---|---|---|
| 20 sessions | ~1,000 | −0.52% | 0.13 | 2022 −3.4 · 2023 −1.1 · 2024 −0.6 · 2025 −0.1 |
| 60 sessions | | −0.84% | 0.14 | |
| 120 sessions | | −0.52% | **0.42** | 2022 **+18.0** · 2023 +5.5 · 2024 +0.5 · 2025 −1.1 · 2026 −4.1 |

The −3.7-point gap was **when** the events happened, not **what** they said. Its sign flips
across years. Independent-director resignations also show nothing: 120d −1.74%, p 0.46.

## Two limits worth knowing

1. **NSE's announcement text is boilerplate.** "…has informed the Exchange regarding Change in
   Auditors." Whether an auditor resigned mid-term (the real red flag) or rotated at an AGM is
   only in the attached PDF. These 2,066 raw events mix both, which dilutes any resignation
   effect. A PDF-reading follow-up could isolate mid-term resignations; the sample would then be
   small (tens, not thousands).
2. Only about half the events price against the candle store (SME and BSE-only names drop out).

## Product decision

- Show Reg-30 events (auditor change, director resignation, default, CIRP, rating action) on a
  symbol's page as **dated facts with the filing link**, the way trader-news shows 8-Ks. Do not
  call them warnings or signals: on 4.5 years of NSE data they predict nothing.
- **Method lesson, adopted for every future event study:** a same-stock random-date placebo is
  not enough. Use a same-date cross-sectional control. Here the weaker one manufactured a
  q = 0.018 "discovery".


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