# マミヤ・オーピー (7991.T) — per-stock model accuracy

> Model predictability decomposition: measures how accurately the ml-factor-lgbm-9f-jp-growth model family predicts this stock's returns within the jp-listed universe. High hit_rate_long does NOT mean 'good stock to buy' -- it means 'the model historically predicted this stock well when selecting it LONG'. This is a property of model-stock fit, not intrinsic stock quality.

- **Name**: マミヤ・オーピー
- **Sector**: 機械
- **Universe**: jp-listed
- **Decomposes**: `ml-factor-lgbm-9f-jp-growth` (strategy verdict: marginal) — https://qbuntu.ai/strategies/ml-factor-lgbm-9f-jp-growth
- **Computed asof**: 2026-10-01T02:33:09
- **HTML**: https://qbuntu.ai/stocks/7991.T
- **JSON**: https://qbuntu.ai/v1/stocks/7991.T
- **License**: CC-BY-4.0

## Accuracy (median across grid)

Median LONG hit rate is 0.3110 — below a coin flip.

| metric | median | p25 | p75 | n |
|---|---:|---:|---:|---:|
| hit_rate_long | 0.3110 | 0.1343 | 0.4277 | 12 |
| hit_rate_short | 0.0417 | 0 | 0.1517 | 11 |
| avg_return_long_bps | -56.8 | -119.5 | -26.6 | 12 |
| avg_return_short_bps | -183.0 | -206.3 | -77.9 | 11 |
| selection_rate_long | 0.0019 | 0.0017 | 0.0020 | 12 |
| selection_rate_short | 0.0003 | 0.0001 | 0.0003 | 12 |

Hit rate ≈ 0.5 means the model's picks on this stock were near coin-flip. Returns in bps/trade. Metrics with n = 0 are omitted; n < 5 is a thin sample.

## PnL contribution

- long: -8.9071
- short: -1.4283
- total: -10.3
- appearances: LONG 1269 / SHORT 160 of 668928

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Research, not investment advice. These metrics describe model–stock fit, not the stock's merit.
Cite as: qbuntu (2026). 7991.T per-stock accuracy. https://qbuntu.ai/stocks/7991.T