hyperfeedeventstrading-halts-api
event_family · market_structure

Trading Halts API.

LULD halts, T1/T2 regulatory halts, circuit breakers, and exchange-initiated suspensions — as typed events with halt code, reason, and resume timestamps. Know the moment a name goes dark.

family_idmarket_structure
event_types5
trailing 30d emitted1,247
audited precision99.7%
median latency12s
What this tracks

Every event_type in market_structure.

Each type emits the same envelope with a family-specific payload. Subscribe to the whole family or filter to specific types.

01
trading_halt_initiated

Exchange or regulator halts trading on a symbol.

02
trading_halt_resumed

Trading resumes after a halt period.

03
luld_pause

Limit Up-Limit Down market-wide or single-stock pause triggered.

04
circuit_breaker_triggered

Market-wide circuit breaker activated (Level 1/2/3).

05
ipo_halt_released

IPO or direct listing halt released for initial trading.

Example event

One real event. Full JSON payload.

This is the exact shape you'd receive via GET /v1/events or via a signed webhook delivery.

Request

GET/v1/events?family=market_structure&event_types=trading_halt_initiated&since=2026-04-01
// Query all market_structure events in the last 14 days
GET /v1/events?family=market_structure&event_types=trading_halt_initiated&since=2026-04-01
Authorization: Bearer hf_live_...

Response · 200 OK

200 OKapplication/json
{
  "event_id": "evt_20260413_aldx_market_structure",
  "schema_version": "2026-04-20",
  "event_type": "trading_halt_initiated",
  "assertion_type": "fact",
  "status": "official_announced",
  "priority": "critical",
  "entity": {
    "ticker": "ALDX",
    "name": "Aldeyra Therapeutics"
  },
  "lifecycle": {
    "detected_at": "2026-04-13T13:42:18Z",
    "announced_at": "2026-04-13",
    "effective_at": "2026-04-13",
    "confirmed_at": "2026-04-13"
  },
  "source": {
    "type": "exchange",
    "name": "NYSE · NASDAQ · CTA",
    "tier": "tier_1"
  },
  "summary": {
    "one_line": "NASDAQ initiated a T1 trading halt on ALDX pending a material news announcement."
  },
  "payload": {
    "halt_code": "T1",
    "halt_reason": "Pending news",
    "exchange": "NASDAQ",
    "halted_at": "2026-04-13T14:32:18Z",
    "resumed_at": null,
    "duration_seconds": null
  },
  "confidence": {
    "overall": 0.98,
    "identity": 0.99,
    "event_classification": 0.98
  }
}
Recent activity · delayed 7d

Recent market_structure events.

Pulled live from the public delayed feed. Click through to the full tape for payloads, lifecycle, and source links.

Apr 13
T1 halt · pending news · 17 min
ALDX· Aldeyra
CRITICAL
Apr 13
LULD pause · volatility · 5 min
TSLA· Tesla
HIGH
Apr 12
T1 halt · M&A announcement
ATVI· Activision
CRITICAL
Apr 11
Circuit breaker L1 · market-wide · 15 min
SPY· S&P 500 ETF
CRITICAL
Apr 10
IPO halt released · initial trading
RDDT· Reddit Inc.
HIGH
Apr 09
SEC suspension · 10-day · fraud concerns
MULN· Mullen Auto
CRITICAL
Sources · where this data comes from

Ranked by authority, merged by entity.

Every event carries a source object. When the same event is confirmed by multiple sources, they merge into one canonical event with an evidence array.

Tier 1 · exchange

NYSE · NASDAQ · CTA

Direct from exchange halt feeds · sub-second latency

Tier 1 · regulator

SEC trading suspensions

Administrative proceedings and 10-day suspensions

Tier 1 · SIP

CQS / UTP SIP

Consolidated tape halt/resume messages

Tier 2 · issuer

Company halt requests

Issuer-requested halts pending material news

Tier 1 · market data

OPRA · options exchanges

Correlated options halt data

Tier 2 · news

Reuters · Bloomberg wire

Contextual reporting on halt reasons

Schema · payload fields

Family-specific fields inside payload.

All events share the same envelope (event_id, entity, lifecycle, sources, assertion_type, confidence). The payloadis what's specific to this family.

FieldTypeDescriptionExample
payload.halt_codestringExchange halt reason code (T1, T2, LUDP, M, etc.)."T1"
payload.halt_reasonstringHuman-readable halt reason."Pending news"
payload.exchangestringPrimary listing exchange."NASDAQ"
payload.halted_atdatetimeExact halt timestamp."2026-04-13T14:32:18Z"
payload.resumed_atdatetime?Resume timestamp, null if still halted.null
payload.duration_secondsinteger?Halt duration in seconds, if resumed.1847
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