源杰科技 (688498) hit limit-down on 2026-10-08: Stock-specific move? After-close breakdown

Price & volume (60 sessions up to the event day)

Risk reference：Close ± 1.5 × ATR14 — a volatility yardstick, not an entry/exit signal

Historical analogue event study

In 2024-09-09~2026-10-08, 7 sessions moved down ≥ 12.0%

Baseline (all sessions): next-day up 54%, avg next +0.77%, avg 5-day +3.71% — no statistically distinguishable edge.

Attribution & commentary

Market mood

688498 hit limit-down on CNY 7.30bn of turnover, ranking among the session's largest decliners — a material downside liquidity shock.

Key data

Closed at CNY 1290.40, -20.00% (daily limit ±20% for this board), turnover CNY 7.30bn, turnover rate 4.48%.

Cause check: Stock-specific move

The STAR 50 moved -4.82% versus -20.00% for the stock, a relative deviation of -15.18 points beyond the 3pp idiosyncratic threshold. Such deviations typically reflect filings, thematic flows or concentrated positioning; drivers should be verified against exchange disclosures. No unverified attribution is made.

Commentary

Two execution biases dominate after sharp declines: failing to honour stops (disposition effect) and premature averaging down (anchoring). Both substitute expectation for a predefined plan.

Volume & volatility

Volume 1.82x the 20-day average; the move ranks at the 100th percentile of daily moves; ATR14 is 7.96% of price.

Historical analogues

7 sessions in 2024-09-09~2026-10-08 moved the same way by ≥ 12.0%. Next-day up rate 86%, average next day +3.09%, average 5-day +12.20%, 5-day continuation 0%, average adverse excursion -16.56%. 95% confidence interval for the next-day up rate: 49%–97%; unconditional baseline across all sessions in the window: 54% up, average next day +0.77%, average 5-day +3.71%. The baseline lies inside the interval: no statistically distinguishable edge versus an ordinary day. Event statistics, not a strategy backtest or forecast.

Risk takeaway

Stops may only be adjusted in the favourable direction. The disposition effect is a principal source of drawdown in individual accounts.

Falsification conditions

This reading treats the session as a single-day downside shock. It is invalidated if, within 5 sessions, price closes below 1136.41 (1.5×ATR14 from the event close), which would indicate a trend rather than a shock; it is also invalidated if price closes above 1444.39, which would indicate the shock has been fully absorbed.

Methodology & disclosures

Data: exchange end-of-day prices via Sina Finance, retrieved after the close; statistics use only sessions whose 5-day outcome was known on the event date (no look-ahead). Attribution compares the stock with its board index only; sector indices, filings and order-flow data are not included. Analogue statistics are event studies, not backtests: samples may overlap and are not tested out of sample. Generated automatically by rules; AI may only rephrase and any text whose numbers or volume wording disagree with the data is discarded. Simulated-practice research; not investment advice. Aegis Quant holds no position in the security.