TradingAgents/docs/agent/decisions/003-yfinance-etf-proxies.md

type	status	date	agent_author	tags	related_files
decision	active	2026-03-17	claude	data yfinance sector-performance	tradingagents/dataflows/yfinance_scanner.py

Context

yfinance.Sector("technology").overview returns only metadata (companies_count, market_cap, etc.) — no performance data (oneDay, oneWeek, etc.).

The Decision

Use SPDR sector ETFs as proxies:

sector_etfs = {
    "Technology": "XLK", "Healthcare": "XLV", "Financials": "XLF",
    "Energy": "XLE", "Consumer Discretionary": "XLY", ...
}

Download 6 months of history via yf.download() and compute 1-day, 1-week, 1-month, YTD percentage changes from closing prices.

Constraints

• yfinance.Sector.overview has NO performance data — do not attempt to use it.
• top_companies has ticker as INDEX, not column. Always use .iterrows().

Actionable Rules

• Always test yfinance APIs interactively before writing agent code.
• Always inspect DataFrame structure with .head(), .columns, and .index.