FIX & Market Model Q&A

Session recovery handles message gaps during logon or after a disconnect. Two methods are supported: message recovery (preferred) and full snapshot recovery.

• Message Recovery (during Logon only): Set NextExpectedMsgSeqNum in your Logon (A) to automatically retrieve missed messages.
• Full Snapshot Recovery: Use when session state is lost/reset (e.g. ResetSeqNumFlag=Y) and rebuild state with snapshot requests such as OrderMassStatusRequest (AF).

Best practice: use message recovery for short disconnects; reset and snapshot for longer gaps.

If your MsgSeqNum is lower than expected, the gateway rejects the message. To recover, either reconnect with ResetSeqNumFlag=Y to reset, or log on with the correct NextExpectedMsgSeqNum to recover messages. ResendRequest is not supported.

• Both gateways are active and identical; sequence numbers are separate per session.
• Maintain dual connections if possible; when switching after a failure, log in with ResetSeqNumFlag=Y and recover state via snapshots (e.g. OrderMassStatusRequest).
• Track via client IDs such as ClOrdID or QuoteMsgID and resend idempotently (duplicates are rejected).

Send a MarketDataRequest (V) with unique MDReqID, specifying desired symbols and data types (bid/offer/trade). The stream continues until you unsubscribe.

The FIX gateway may enforce throttling based on system load; excessive message rates can cause dropped messages or session disconnects. Use batching and pacing appropriately.

Orders match on price–time priority. At the same price, earlier arriving orders execute first; if simultaneous, deterministic internal timestamps break ties. The exception to this are internal trades, which get the highest priority.

Supported order types include Limit, Market, Iceberg (with disclosed quantity), Fill-Or-Kill (FOK), and Immediate-Or-Cancel (IOC). Each follows specific visibility and matching rules.

The market supports Opening, Closing, and Intraday auctions. During these phases, orders match at the price that maximizes trade volume. Indicative prices and volumes are published periodically.

Outbound TradeCaptureReport messages from the exchange include a TradeReportID that is globally unique. For inbound reports, participants assign the ID; responses mirror it in TradeReportRefID.

If your organization already has support portal access, submit a request for new network connections or market access via the NGM Support Portal. If not, email support@ngm.se to set up the necessary accounts.