longbridge-etf-analysis

name	longbridge-etf-analysis
description	ETF analysis framework via Longbridge — product screening (AUM/expense ratio/index), tracking error, liquidity (bid-ask spread/volume), premium/discount (NAV vs market price), and A-share ETF allocation insights. Triggers: "ETF分析", "ETF选择", "ETF跟踪误差", "ETF溢价", "ETF流动性", "ETF费率", "ETF规模", "宽基ETF", "行业ETF", "指数基金", "ETF分析", "ETF選擇", "ETF追蹤誤差", "ETF溢價", "ETF流動性", "ETF費率", "ETF規模", "指數基金", "ETF analysis", "ETF selection", "tracking error", "ETF premium discount", "ETF liquidity", "expense ratio", "broad market ETF", "sector ETF", "index fund".
license	MIT
metadata	{"author":"longbridge","version":"1.0.0","risk_level":"read_only","requires_login":false,"default_install":true,"requires_mcp":false,"tier":"analysis"}

longbridge-etf-analysis

Prompt-only analysis skill. Analyses ETFs across five dimensions: product profile, tracking error, liquidity, premium/discount, and allocation fit — supporting both US-listed ETFs and A-share ETFs.

Response language: match the user's input language — Simplified Chinese / Traditional Chinese / English.

When to use

• "QQQ 和 QQQM 哪个更适合长期持有？" / "QQQ vs QQQM for long-term holding?"
• "这只 ETF 的跟踪误差大不大？" / "Is the tracking error on this ETF high?"
• "510300 现在溢价还是折价？" / "Is 510300 trading at a premium or discount?"
• "帮我分析沪深300 ETF 的流动性" / "Analyse the liquidity of CSI 300 ETFs"
• "行业 ETF 怎么选？" / "How to pick a sector ETF?"

For index constituent stocks route to longbridge-constituent. For individual stock valuation route to longbridge-valuation.

CLI

Run longbridge <subcommand> --help to verify exact flags.

# ETF quote — price, volume, market cap, turnover
longbridge quote <ETF_SYMBOL> --format json

# Constituent holdings — underlying stocks and weights
longbridge constituent <ETF_SYMBOL> --format json

# Historical price — compute tracking error vs index
longbridge kline <ETF_SYMBOL> --period day --count 60 --format json

# Index / benchmark price for comparison
longbridge kline <BENCHMARK_SYMBOL> --period day --count 60 --format json

# Valuation indices (PE/PB of ETF if available)
longbridge calc-index <ETF_SYMBOL> --format json

Five-dimension analysis

1. Product profile

Extract from quote + constituent output:

• Underlying index tracked
• AUM / total market cap (proxy)
• Expense ratio (if available in quote metadata; otherwise note "check fund prospectus")
• Inception date / listing exchange

2. Tracking error

• Fetch ETF daily kline and benchmark daily kline (60 bars).
• Daily return difference: d_i = r_ETF_i − r_index_i
• Tracking error (annualised): TE = std(d) × √252
• Interpretation: TE < 0.3% excellent; 0.3–1% acceptable; > 1% investigate.

3. Liquidity

From quote:

• Average daily volume and turnover
• Bid-ask spread (if tick data available; otherwise use turnover-rate as proxy)
• Liquidity flag: turnover-rate > 0.5% = liquid; < 0.1% = illiquid (A-share ETFs)

4. Premium / discount (NAV vs market price)

• For A-share ETFs: premium = (market price − NAV) / NAV × 100%
• NAV may not be in real-time quote; note this and use EOD NAV if available.
• Persistent premium > 2% or discount < −2% signals arbitrage opportunity or liquidity issue.
• For US ETFs: premium/discount is typically < 0.1% due to continuous creation/redemption.

5. Allocation fit

• Index type: broad market (SPY/QQQ/510300) vs sector (XLK/515790) vs factor (value/growth/momentum)
• Currency and market exposure
• Overlap analysis: if user holds multiple ETFs, flag significant holdings overlap from constituent

Workflow

1. Resolve ETF symbol to <CODE>.<MARKET> (e.g. SPY.US, 510300.SH).
2. Concurrently fetch: quote, constituent, ETF kline, benchmark kline.
3. Compute TE, assess liquidity, estimate premium/discount.
4. Summarise all five dimensions.
5. Output structured report (template below). Cite Longbridge Securities.

Output template

{ETF Symbol} analysis — Source: Longbridge Securities

[1. Product profile]
- Index tracked: {name}  |  Exchange: {ex}
- AUM proxy (mkt cap): {$X}  |  Expense ratio: {X% / see prospectus}

[2. Tracking error (60-day)]
- Annualised TE: X%  → {excellent / acceptable / elevated}

[3. Liquidity]
- Avg daily volume: {X}  |  Turnover rate: X%  → {liquid / moderate / illiquid}
- Bid-ask spread estimate: {X% / data unavailable}

[4. Premium / Discount]
- Latest: {+X% premium / −X% discount / ~flat}
- Note: {A-share ETF — NAV published after close / US ETF — near-zero typical}

[5. Allocation fit]
- Type: {broad market / sector / factor}
- Key holdings (top 5): {list from constituent}
- Currency exposure: {USD / CNY / HKD}

[Summary]
{2–3 sentence overall assessment}

⚠️ 以上分析仅供参考，不构成投资建议。/ 以上分析僅供參考，不構成投資建議。/ For reference only. Not investment advice.

Error handling

Situation	简体回复	繁體回復	English reply
command not found: longbridge	切换到 MCP；若不可用，请安装 longbridge-terminal	切換至 MCP；若不可用，請安裝 longbridge-terminal	Fall back to MCP; if unavailable, install longbridge-terminal
stderr not logged in	请执行 longbridge auth login	請執行 longbridge auth login	Run longbridge auth login
constituent returns empty	持仓数据暂不可用，跳过重叠分析	持倉數據暫不可用，跳過重疊分析	Constituent data unavailable; skipping overlap analysis
Benchmark kline unavailable	无法计算跟踪误差，仅显示 ETF 本身收益	無法計算追蹤誤差，僅顯示 ETF 本身收益	Cannot compute TE; showing ETF return only

MCP fallback

When the CLI is unavailable, fall back to the MCP server. Discover available tools from the MCP server's tool list at runtime — do not rely on hardcoded tool names.

Related skills

• Constituent stock list → longbridge-constituent
• Individual stock valuation → longbridge-valuation
• Capital flow into ETF holdings → longbridge-capital-flow
• Market / index temperature → longbridge-market-temp

File layout

longbridge-etf-analysis/
└── SKILL.md          # prompt-only, no scripts/