{
  "result": {
    "date": "20260918",
    "name": "코스피",
    "name_en": "KOSPI",
    "family": "KOSPI시리즈",
    "family_en": "KOSPI Series",
    "constituent_count": 828,
    "is_computed_index": false,
    "close": 6894.23,
    "change": 178.82,
    "change_pct": 2.66,
    "open": 6885.7,
    "high": 6914.08,
    "low": 6830.95,
    "volume": 346806906,
    "trading_value_krw": 28104963033556,
    "market_cap_krw": 5684350905680993,
    "year_high": 9114.55,
    "year_high_date": "2026-06-22",
    "year_low": null,
    "year_low_date": null,
    "year_low_not_measured": "연최저=0과 짝지은 연최저일(2026-09-21)이 스냅샷 일자(20260918)보다 미래다 — 소스가 아직 못 채운 자리에 심어 둔 판박이값(sentinel)이지 실제 0이 아니다",
    "base_date": null,
    "base_index": 100,
    "ytd_change_pct": 63.6
  },
  "coverage": {
    "source": "Korea public data portal + KRX index series",
    "snapshot_date": "20260918",
    "source_file": "archive/raw/indices/20260918.ndjson",
    "built_at": "21 September 2026, 11:16 KST",
    "rows": 171,
    "with_name_en": 168,
    "with_year_low": 6,
    "year_low_not_measured": 165,
    "note": "yearLow (and its date) is null whenever the source reported exactly 0 — in the 20260918.ndjson snapshot, 165 of 171 rows carried a 0 that was paired with a yearLowDate one day after the snapshot date itself, an impossible value. That is a source placeholder, not a real annual low of zero. See yearLowNotMeasured per row.",
    "why_rows_are_kept": "Rows that could not be fully measured are kept, with the reason in the relevant *NotMeasured column. Dropping them would remove the denominator."
  }
}