Stock Sentiment Gauge

CEV-OS / Data API / Stock Sentiment Gauge

CEV-OS Data API · last updated 2026-11-04. Status: live. Version 1.

Use this when you need a 0-100 US stock-market fear/greed reading with its eight component percentiles and recent daily history (cev-os's own index; IEX ETF closes + US Treasury yields).

What it is

cev-os's own US stock sentiment index (not CNN Fear & Greed). Eight components from ETF closes (SPY, RSP, HYG, IEF, TLT and the nine sector SPDRs) and the 10-year Treasury par yield: momentum (SPY vs 125-day average), strength (sector 52-week range position), breadth (sectors above 50-day average + RSP vs SPY), vol_term (SPY 10/60-day realized vol, inverted), junk (HYG vs IEF), volatility (SPY 20-day realized vol vs its 50-day mean, inverted), yield10 (20-day change in the 10-year yield) and safe_haven (SPY vs TLT). Each is a trailing 504-session percentile; the weighted blend gets a 3-day EMA. Bands: Extreme Fear 0-25, Fear >25-45, Neutral >45-55, Greed >55-75, Extreme Greed >75. Prices are IEX last sale (IEX venue only), split-adjusted, not dividend-adjusted. Daily, prior session.

Endpoints

REST: GET /v1/stock-sentiment on https://api.cev-os.com
Legacy host (same service): GET /v1/stock-sentiment on https://cev-os.com
MCP tool: get_stock_sentiment on https://mcp.cev-os.com/mcp

Parameters

Query parameters for `GET /v1/stock-sentiment`
Name	Type	Description	Constraints
`days`	integer	Days of history to return (1-60, default 30).	example 30; min 1; max 60

Example request

No account and no key. Query values below are the examples or defaults from the registry. An optional free key (header x-api-key) raises the limits; create one at https://cev-os.com/#api_keys after signing in with a verified email (Google sign-in is already verified).

curl -s "https://api.cev-os.com/v1/stock-sentiment?days=30"

Example response

Every /v1 response is a JSON envelope (schema_version, product, timestamps, license, attribution, data). The registry example is the data member:

{
  "id": "stock_sentiment_gauge",
  "date": "2026-10-29",
  "value": 27.2,
  "classification": "Fear",
  "previous": 25.5,
  "change": 1.7,
  "components": [
    {
      "id": "momentum",
      "weight": 0.214,
      "percentile": 21.9
    }
  ],
  "history": [
    {
      "date": "2026-10-28",
      "value": 25.5,
      "classification": "Fear"
    }
  ]
}

Update frequency

Daily, prior US session: IEX closes land T+1; recomputed 7:45 AM ET (retries 10:45 AM and 1:45 PM ET); cached 5 min.

Public cache: 300 seconds (Cache-Control: public, max-age=300).

Sources, license and usage

License status: cleared with attribution. Computed only from IEX Historical Data (redistribution and resale permitted with the exact IEX attribution text and a link to its terms, included in each response) and U.S. Treasury par yields (public domain). No FRED, Cboe, Yahoo or CNN data.

Underlying sources
Source	License	commercialOk	Terms
CEV-OS Stock Sentiment Gauge (own method, v2 no-Cboe recipe)	Own work (Cutting Edge Ventures); computed only from the IEX and U.S. Treasury inputs listed	true	—
IEX Historical Data (HIST TOPS), daily IEX last sale	Free; redistribution and resale permitted with the IEX attribution text and a link to the IEX Historical Data Terms of Use. IEX-venue trades only; IEX describes it as a reference point, not a basis for trading decisions; no warranty.	true	https://www.iex.io/legal/hist-data-terms
U.S. Department of the Treasury, Daily Treasury Par Yield Curve Rates (10-year), keyless CSV	US Government work (17 U.S.C. 105, public domain); no key; credit requested; no Treasury endorsement implied	true	https://home.treasury.gov/subfooter/privacy-policy

Attribution (show this wherever you display the data):

Data provided for free by IEX. By accessing or using IEX Historical Data, you agree to the IEX Historical Data Terms of Use.
IEX Historical Data Terms of Use: https://www.iex.io/legal/hist-data-terms
10-year yield: U.S. Department of the Treasury, Daily Treasury Par Yield Curve Rates. Index: CEV-OS Stock Sentiment Gauge (cev-os).

IEX Historical Data Terms of Use

Privacy class: public-derived. Access: public. Price: free (price is null; pay-per-call is not active).

Gaps

IEX last sale, not the official consolidated close; not dividend-adjusted.
Realized volatility stands in for the VIX, so the gauge can lag implied-volatility gauges by about a day at sharp turns.
History starts 2026-04-23 (IEX store begins 2023-04-20; 756 sessions of warm-up).

Disclaimer

A sentiment gauge for information only, built on IEX-venue reference prices. Research found no trading edge. Not investment advice.

Data API hub (all products, limits, license notes)
MCP Registry listing com.cev-os/data
OpenAPI 3.1
Machine product list: /v1/products

Reference data, not investment advice.