> ## Documentation Index
> Fetch the complete documentation index at: https://docs.focusalpha.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Screen ETFs by Portfolio Shape

> Filter ETFs by measured holdings characteristics — number of holdings, top-10 concentration, large- and small-cap share, bond duration and treasury share.

Screening ETFs by portfolio shape filters on measurements taken directly from each fund's newest holdings day: how many positions it holds, how concentrated the top of the book is, how its equity weight splits across cap bands, and — for bond funds — its duration and treasury share. These are measured numbers, not labels, so they work on any fund with a holdings feed regardless of how it is classified.

<Info>
  **Plan:** Fund · **Credits:** 1 per call; screen facets are free
</Info>

## The Concentration Filters

<ParamField query="min_n_holdings" type="number">
  Floor on the number of holdings lines.
</ParamField>

<ParamField query="min_top10_share" type="number">
  Floor on the share of the book in the ten largest positions, `0..1`. `max_top10_share` sets the ceiling — the way to require diversification.
</ParamField>

## The Cap-Band Filters

<ParamField query="min_large_share" type="number">
  Floor on the large-cap share of linked equity weight, `0..1`. `max_large_share` sets the ceiling.
</ParamField>

<ParamField query="min_small_share" type="number">
  Floor on the small-cap share of linked equity weight, `0..1`.
</ParamField>

Cap bands are **measured**, not labels: sector and thematic funds carry no cap-band label at all, so "large-cap biotech" is a segment plus specialization plus `min_large_share` — see [Screen ETFs by Asset Class](/screening/etf/by-asset-class).

## The Bond-Book Filters

<ParamField query="min_duration" type="number">
  Floor on weighted bond duration, in years. `max_duration` sets the ceiling — `max_duration=1` is the ultra-short bucket.
</ParamField>

<ParamField query="min_treasury_share" type="number">
  Floor on the treasury share of the bond book, `0..1`.
</ParamField>

## Where These Numbers Come From

Every filter on this page reads the fund's holdings profile, computed from the newest holdings day of its portfolio — the same measurement layer served in the `portfolio` block of the [ETF profile](/etf/overview). Funds without a holdings feed have nulls here and silently drop out of these filters; the free facets endpoint reports how many funds carry a holdings profile. On exposure-hidden funds the profile is computed on notional exposure, not raw market values.

## Related Screens

[By geography](/screening/etf/by-geography) · [By asset class](/screening/etf/by-asset-class) · [ETF holdings](/etf/holdings) · [ETF screening overview](/etf/screening)

<RequestExample>
  ```bash Concentrated sector books theme={null}
  curl "https://api.focusalpha.ai/v1/etfs/screen?segment=equity.sector.health_care&min_top10_share=0.5" \
    -H "Authorization: Bearer $FOCUSALPHA_API_KEY"
  ```

  ```bash Short-duration treasuries theme={null}
  curl "https://api.focusalpha.ai/v1/etfs/screen?max_duration=1&min_treasury_share=0.9" \
    -H "Authorization: Bearer $FOCUSALPHA_API_KEY"
  ```
</RequestExample>

<ResponseExample>
  ```json Response (XLV, fields trimmed) theme={null}
  {
    "data": [
      {
        "ticker": "XLV",
        "name": "State Street Health Care Select Sector SPDR ETF",
        "n_holdings": "62",
        "top1_share": "0.1507",
        "top10_share": "0.6082",
        "large_share": "0.8534",
        "mid_share": "0.1466",
        "small_share": "0.0000",
        "duration": null,
        "treasury_share": "0.0000"
      }
    ]
  }
  ```
</ResponseExample>