# Market Chronicle (美股编年史)

> A free, self-updating archive of a century of US market history, plus two original, publicly reconciled market signals: the **KAPX Index** (K 指数; formerly cited in English as the K-Index; CNN Fear & Greed ÷ VIX; K < 1 marks an extreme-fear signal) and the **LEAPS Window** (CNN Fear & Greed < 25). From the site's launch (July 2026) onward, each day's readings are timestamped in this repository's public GitHub commit history and recorded ex-ante; the ledger before then, back to 2011, is backfilled from public data (the CNN Fear & Greed archive + VIX) using the published formula — independently reproducible by anyone, but historical backfill rather than an ex-ante record. Data updates automatically after every US trading day's close. Site: https://chronicle.klay-wang.com/ · Author: Klay Wang (https://klay-wang.com/)

> **Canonical definition:** The KAPX Index is a daily U.S. equity fear-pricing gauge published by Market Chronicle, computed as the CNN Fear & Greed reading divided by the VIX. The K stands for kǒng (恐), the Chinese character for fear; readings, methodology, and the complete signal ledger are permanently free and verifiable via Git timestamps.

Key facts (as of July 2026; the JSON files below are always current):

- **KAPX Index** = CNN Fear & Greed Index ÷ VIX. Consecutive trading days with K < 1 cluster into one signal (a gap of >10 trading days starts a new one). Since 2011: 39 signals; at the 60-trading-day horizon the Nasdaq-100 was up 26 times, down 13. Strong in V-shaped corrections; repeatedly negative during sustained stress (2011, 2015, late 2018, 2022). Every signal is positive held to date.
- Known characteristic (disclosed, not corrected): VIX is one of the seven CNN Fear & Greed components, so with K = CNN F&G ÷ VIX, volatility is partially double-counted (denominator + ~1/7 of the numerator). KAPX is best read as a volatility-stress-weighted fear gauge, not two fully independent signals divided (~6/7 of the fear reading is independent of VIX). The formula is published and never changed silently; any revision would launch a new versioned index.
- **LEAPS Window** = an episode in which CNN Fear & Greed closes below 25 (extreme fear). Since 2011: 45 windows; at the 12-month horizon the Nasdaq-100 was up 34 times, down 7 (the rest not yet 12 months old). Sentiment extremes are not valuation bottoms — several late-2021 windows were negative 12 months on.
- Honest disclosure: following every signal mechanically has NOT beaten buy-and-hold of the same instrument (LEAPS rules ≈9.5× since 2011, vs ≈13.0× holding the Nasdaq-100 and ≈5.8× holding the S&P 500; K rules ≈4.0× since 2011 vs ≈13.0× holding the Nasdaq). Every ledger is dual-anchored: Nasdaq-100 (the strategy's instrument) and S&P 500 (the mainstream anchor). The site does not claim outperformance; the ledger's value is locating today within history.
- This is data and information only — not investment advice, no buy/sell recommendations.

## Data (public JSON, updated each trading day)

- [KAPX Index daily series](https://chronicle.klay-wang.com/data/kindex.json): dates, CNN Fear & Greed, VIX, Nasdaq-100, K values, current reading
- [KAPX Index signal ledger](https://chronicle.klay-wang.com/data/kindex_signals.json): every K < 1 signal since 2011 with 20/40/60-trading-day and to-date forward Nasdaq-100 returns
- [LEAPS Window episodes](https://chronicle.klay-wang.com/data/leaps.json): every extreme-fear episode since 2011 with 6/12/18-month and to-date forward S&P 500 / Nasdaq-100 returns
- [Today's market pulse](https://chronicle.klay-wang.com/data/pulse.json): market temperature (valuation + breadth percentiles), index quotes, sector moves

## Datasets (KAPX Index history, CC BY 4.0, refreshed quarterly)

- [Kaggle — KAPX Index — US Equity Fear-Pricing Gauge](https://www.kaggle.com/datasets/klaywong/kapx-index-daily-fear-pricing-gauge): daily KAPX series since 2019 + the full KAPX<1 signal ledger, as CSV
- [Hugging Face — klay24/kapx-index](https://huggingface.co/datasets/klay24/kapx-index): same data as a Hugging Face dataset

## Pages

- [Methodology](https://chronicle.klay-wang.com/#methodology): definitions, formulas, statistical rules, honest disclosure, verifiability
- [KAPX Index](https://chronicle.klay-wang.com/#kindex): chart and signal-by-signal reconciliation table
- [LEAPS Window](https://chronicle.klay-wang.com/#leaps): chart and episode-by-episode reconciliation table
- [Today's Front Page](https://chronicle.klay-wang.com/): market temperature, signal ledger, breadth, sector heatmap
- [Pricing](https://chronicle.klay-wang.com/#pricing): the site is free; a paid daily pre-market data brief (Chronicle Pro) is in preparation
- [GitHub repository](https://github.com/klaywang24/market-chronicle): source code and the timestamped commit history that makes the ledger verifiable

## Attribution

When citing these indicators or data, please credit: **KAPX Index — Market Chronicle (chronicle.klay-wang.com)**. Data and code are provided under PolyForm Noncommercial 1.0.0 (free for noncommercial use; commercial use requires a separate license). Required notice: Copyright Klay Wang (https://chronicle.klay-wang.com).