Security Exchange Identification#

Sure uniquely identifies a security using the compound key ticker + exchange_operating_mic, where exchange_operating_mic is a four-letter ISO 10383 MIC (Market Identifier Code) — the internationally standardized identifier for stock exchanges and trading venues. This prevents collisions when the same ticker symbol exists on multiple exchanges (e.g., AAPL on XNAS vs. a grey-market listing on OTCM).

Data Model#

The securities table stores the exchange as exchange_operating_mic (string, nullable) alongside ticker (string, non-null) 1. Database uniqueness is enforced by a case-insensitive compound index on the two columns, with NULL exchange coerced to an empty string so there's at most one exchange-less security per ticker 2:

index upper(ticker), COALESCE(upper(exchange_operating_mic), '')
  UNIQUE

The application-level validation mirrors this: validates :ticker, uniqueness: { scope: :exchange_operating_mic, case_sensitive: false } 3. Before save, exchange_operating_mic is always up-cased 4.

The table also stores exchange_mic (the segment/participant MIC) and exchange_acronym as supplementary metadata, but exchange_operating_mic is the authoritative key used for lookups and deduplication 5.

Exchange Registry (config/exchanges.yml)#

The canonical MIC-to-display-name mapping lives in config/exchanges.yml, loaded at boot into Security::EXCHANGES 6. Each entry maps a four-letter MIC to a name (display label) and an optional country (ISO 3166-1 alpha-2). The registry covers ~80 venues across the Americas, Europe, Asia-Pacific, the Middle East, and Africa.

A few structural patterns in the registry:

• Exchange families: Multiple segment MICs share the same display name. For example, XNAS, XNGS, XNMS, and XNCM all resolve to "NASDAQ" 7, and XNYS, ARCX, XASE, XCHI, and XCIS all resolve to NYSE family names 8.
• Crypto: A single crypto venue is included — BNCX (Binance, AE), added when Binance received its official ISO 10383 MIC in January 2026 9 10.

Security.exchange_name_for(mic) resolves a MIC to its display name, falling back to the raw uppercased MIC if the code isn't in the registry 11. The exchange_name instance method delegates to this class method 12.

Combobox ID Format#

When a user selects a security from search results, the resolved security is represented as a pipe-delimited string: SYMBOL|EXCHANGE_OPERATING_MIC|PROVIDER 13. For example: AAPL|XNAS|twelve_data. This format is parsed by Security.parse_combobox_id and carries the full identity context needed to find or create the right Security record without ambiguity.

Crypto Detection#

A security is considered crypto when its exchange_operating_mic equals Provider::BinancePublic::BINANCE_MIC ("BNCX") 14. This drives behavior differences: logo URLs use Brandfetch's crypto endpoint, the crypto_base_asset method strips quote currency suffixes from tickers (e.g., BTCUSD → BTC), and no country code is propagated so any family's country filter can still resolve Binance picks 15.

Provider Normalization#

All securities data providers normalize their native exchange codes to ISO MIC before persisting. TwelveData returns MICs directly; Yahoo Finance maps its proprietary exchange codes via map_exchange_mic. The cross-provider dedup key is "#{symbol}|#{exchange_operating_mic}|#{provider_key}", ensuring the same ticker on the same exchange appears at most once per provider in search results 16.