Longbridge Etf 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

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/