How to Read A-Share Sector Rotation

Why sectors before stocks

A single stock can move on a headline; an entire sector moving usually means money is choosing a direction. Fix the direction first, then pick names inside it — that order works better than the reverse.

Three steps: ① ranking (who is rising) → ② valuation percentile (expensive?) → ③ supply chain (why).

Step 1: today’s sector gainers

import requests

KEY = "ct-your-key"
r = requests.get("https://api.ashareapi.com/v1/sector",
                 headers={"Authorization": "Bearer " + KEY}, timeout=15)
b = r.json()
rows = b.get("structured") or b["data"]

for row in rows[:10]:
    print(row)   # sector name / change % / leading stock / advancers & decliners

• Covers industry / concept / region sectors
• Read advancers vs decliners first: a sector up with only 1–2 names rising is leader-driven, not broad

Step 2: is this sector expensive? (valuation percentile)

# Sector codes look like pt01801780 (Shenwan sector)
r = requests.get("https://api.ashareapi.com/v1/sector-valuation",
                 headers={"Authorization": "Bearer " + KEY},
                 params={"code": "pt01801780"}, timeout=15)
print(r.json().get("structured") or r.json()["data"])
# Returns: PE / PB / PS / PCF + dividend yield + historical percentile

• The percentile is the point: whether PE 20x is high depends on its own history
• ≥ 80% → expensive (worse odds); ≤ 20% → cheap (but ask *why* it is cheap)
• Sector codes start with `pt` (e.g. `pt01801780`), not stock codes

Step 3: where is the logic? (supply chain)

# Where a stock sits in its supply chain
r = requests.get("https://api.ashareapi.com/v1/industry-chain",
                 headers={"Authorization": "Bearer " + KEY},
                 params={"mode": "stock", "code": "sh600667"}, timeout=15)
print(r.json().get("structured") or r.json()["data"])
# Returns: chain theme / node / upstream-midstream-downstream / relevance / business description

# Reverse: the chain graph of a theme (which companies, at which positions)
r = requests.get("https://api.ashareapi.com/v1/industry-chain",
                 headers={"Authorization": "Bearer " + KEY},
                 params={"mode": "graph", "topic": "semiconductor"}, timeout=15)

• `mode=list` → all themes (183) · `mode=graph&topic=X` → graph · `mode=stock&code=X` → single stock
• Why it matters: when a sector runs, knowing who supplies whom beats reading concept tags

Combining: "strong + not expensive + has logic"

Common mistakes and boundaries

• Wrong sector code → must start with `pt` (e.g. `pt01801780`); stock codes will not work
• One day only → single-day sector moves are noisy; look at 5/20-day too
• Treating cheap as a buy reason → cheap can be a value trap (a declining industry)
• Relevance is not a position → high relevance means business overlap, not price synchronicity
• Rate limits → sector endpoints need a key; anonymous access covers only the five free endpoints