# x402-factory S&P 500 Positive This Year Probability

> x402-factory S&P 500 Positive This Year Probability is a paid API for AI agents from x402-factory.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-14).

Returns real-time prediction-market probability that the S&P 500 will finish the year positive (close above 7000 on Dec 31), aggregated across Kalshi and Polymarket, via micropayment (x402/USDC).

## Facts

- Endpoint: GET https://x402-factory.com/v1/evergreen/sp500-positive-this-year
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-factory-s-p-500-positive-this-year-probability-10857bd2
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_KPzQQcmiZZGQoWDb5kMYJ

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 x402-factory-s-p-500-positive-this-year-probability-10857bd2
```

Example prompt: What's the current prediction market probability — across Kalshi and Polymarket — that the S&P 500 closes above 7000 and finishes positive this year, and is there a meaningful divergence between the two venues?

## When to prefer this

Choose this endpoint when you need a real-time, cross-venue aggregated probability for the S&P 500 annual outcome with liquidity and volume context. It is preferable to scraping Kalshi or Polymarket individually because it normalizes data across both venues, computes divergence, and provides a single consensus probability. Use it for macro research, portfolio decision support, or detecting arbitrage signals between prediction markets. Requires micropayment via x402 protocol (USDC on Base, $0.02/call).

## Known failure modes

- HTTP 402 returned on first call without payment — agent must parse payment requirements and retry with X-PAYMENT header containing valid USDC on Base
- Insufficient USDC balance causes payment failure and request rejection
- Market may roll to next slug if resolution date passes — check current_slug in response
- Stale or unavailable venue data may reduce per_venue array to fewer than two entries
- Network timeouts if called during high-traffic periods on prediction market APIs

## How this service works

Paid data APIs for AI agents: prediction-market analytics, weather intelligence, weather×market edge signals, and SEC/gov data. Paid endpoints use the x402 protocol (HTTP 402 + USDC on Base): call without payment to receive requirements, retry with an X-PAYMENT header. Machine-readable catalog: /llms.txt. Per-endpoint docs: /docs/{id}.

## Output

Returns a JSON object with the aggregated implied probability (e.g. 0.3812) that the S&P 500 closes above 7000 on December 31, per-venue breakdowns from Kalshi and Polymarket (each with implied probability, market ID, 24h USD volume, and liquidity score), a divergence score between venues, resolution date, resolution criteria summary, and metadata including data freshness and source list.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "properties": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "data": {
   "slug": "sp500-close-above-7000-2026-12",
   "topic": "sp500-positive-this-year",
   "category": "economics",
   "question": "Will the S&P 500 close above 7000 on December 31?",
   "per_venue": [
    {
     "venue": "kalshi",
     "implied_p": 0.4022,
     "market_id": "KXSP500CLOSEABOV",
     "volume_24h_usd": 182273.22,
     "liquidity_score": 0.921
    },
    {
     "venue": "polymarket",
     "implied_p": 0.367,
     "market_id": "sp500-close-above-7000-2026-12",
     "volume_24h_usd": 154584.53,
     "liquidity_score": 0.949
    }
   ],
   "divergence": 0.0352,
   "probability": 0.3812,
   "current_slug": "sp500-close-above-7000-2026-12",
   "last_move_1h": 0,
   "topic_question": "Will the S&P 500 finish the year positive?",
   "resolution_date": "2026-12-31",
   "rolls_to_next_at": "2026-12-31",
   "resolution_criteria_summary": "Resolves YES if the official closing level on the last trading day exceeds 7000."
  },
  "meta": {
   "docs": "https://x402-factory.com/docs/probability.evergreen.sp500-positive-this-year",
   "sources": [
    "kalshi",
    "polymarket"
   ],
   "version": "1.0.0",
   "endpoint": "/v1/evergreen/sp500-positive-this-year",
   "data_mode": "live",
   "freshness": "realtime",
   "request_id": "req_00000000",
   "generated_at": "2026-08-21T03:58:58.097Z"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-factory-s-p-500-positive-this-year-probability-10857bd2/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-factory.com](https://www.zero.xyz/host/x402-factory.com/llms.txt)