# Scale category code

| Code          | Description                                                                              |
| ------------- | ---------------------------------------------------------------------------------------- |
| TOPIX Core30  | Constituents of the TOPIX Core30 index                                                   |
| TOPIX Large70 | Constituents of the TOPIX Large70 index                                                  |
| TOPIX Mid400  | Constituents of the TOPIX Mid400 index                                                   |
| TOPIX Small 1 | Constituents of the TOPIX Small 500 index                                                |
| TOPIX Small 2 | Constituents of the TOPIX Small index that are not included in the TOPIX Small 500 index |
| -             | Issues that fall into none of the categories                                             |

> **Info**
>
> - The scale category indicates the TOPIX size-based index category.
> - We do not provide the effective date of a change to this field itself. However, the `Date` (information effective date) in the response is the applicable date, so you can retrieve the scale category as of any point in time by specifying `date`.

## About TOPIX Small 1

- The scale categories `TOPIX Small 1` and `TOPIX Small 2` have existed since before 2018 (a scale category and an index are different concepts).
- The scale category code in this API is determined using index codes rather than the scale category itself. Specifically, constituents of the TOPIX Small 500 index are set to `TOPIX Small 1`, and the other TOPIX Small constituents are set to `TOPIX Small 2` (the constituents of the TOPIX Small 500 index are identical to the issues classified as TOPIX Small 1 by scale category).
- Because calculation of the TOPIX Small 500 index started with a base date of August 31, 2018, no constituent data exists for dates before that. Therefore, **for dates before August 31, 2018, issues that belong to TOPIX Small 1 by scale category are returned as `TOPIX Small 2`**. TOPIX Small 1 for that period cannot be retrieved from this API.