# HALOWERK Pearson Correlation Matrix Calculator

> HALOWERK Pearson Correlation Matrix Calculator is a paid API for AI agents from handel.halowerk.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-21).

Computes a Pearson correlation matrix from caller-supplied return series, returning pairwise correlation coefficients for up to 10 named series.

## Facts

- Endpoint: POST https://handel.halowerk.com/v1/rechner/correlation?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/halowerk-pearson-correlation-matrix-calculator-4921a062
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Q9BpJtUG_6FTqVqbkr32D

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability halowerk-pearson-correlation-matrix-calculator-4921a062 -d '<json body>'
```

Example prompt: Calculate the Pearson correlation matrix for these three return series: 'SPY' with returns [0.01, -0.02, 0.015, 0.005, -0.01], 'BTC' with returns [0.03, -0.05, 0.02, 0.01, -0.03], and 'GLD' with returns [-0.005, 0.01, -0.002, 0.008, 0.003].

## When to prefer this

Choose this endpoint when you need a pure computation of Pearson correlations on return data you already hold and have pre-aligned temporally. It is ideal for portfolio analytics pipelines, risk model construction, or pair-selection workflows where you supply your own data and want a fast, stateless calculation without any brokerage connectivity, market data fetching, or investment advice. Prefer it over general-purpose statistics libraries when you need a microservice-style, pay-per-call compute node integrated into an agentic workflow.

## Known failure modes

- Series with fewer than 2 data points rejected (minItems: 2 per series)
- Constant series (all identical values) return null correlation coefficients — not an error, but caller must handle null
- More than 10 series submitted returns validation error (maxItems: 10)
- Series with more than 5000 data points rejected (maxItems: 5000)
- Misaligned time series produce mathematically valid but economically meaningless correlations — caller must pre-align data
- Missing required 'name' or 'returns' fields cause request rejection
- Payment failure via x402 protocol prevents execution

## How this service works

Pearson-Korrelationsmatrix. Reihen müssen vom Aufrufer zeitlich ausgerichtet sein. Konstante Reihen haben undefinierte Korrelation (null). Alle Zahlen, Kurse und Vorgaben liefert der Aufrufer. Keine eigenen Kursdaten, kein Brokerzugriff, keine Ausführung. Rechenwerkzeug, keine Anlageberatung, keine Empfehlung.

## Output

A Pearson correlation matrix containing pairwise correlation coefficients for all submitted named return series. Values range from -1.0 (perfect negative correlation) to 1.0 (perfect positive correlation). Constant series (zero variance) return null for their correlation entries. The matrix is symmetric with 1.0 on the diagonal.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "series": {
   "type": "array",
   "items": {
    "type": "object",
    "required": [
     "name",
     "returns"
    ],
    "properties": {
     "name": {
      "type": "string",
      "maxLength": 64,
      "minLength": 1
     },
     "returns": {
      "type": "array",
      "items": {
       "type": "number",
       "maximum": 1000000000000,
       "minimum": -1000000000000
      },
      "maxItems": 5000,
      "minItems": 2
     }
    },
    "additionalProperties": false
   },
   "maxItems": 10,
   "minItems": 1
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/halowerk-pearson-correlation-matrix-calculator-4921a062/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from handel.halowerk.com](https://www.zero.xyz/host/handel.halowerk.com/llms.txt)