Market Data & Reference Data platforms deliver the real-time and historical financial information that powers trading systems, risk engines, and portfolio management workflows. These platforms provide standardized pricing feeds, security identifiers, corporate actions, and instrument characteristics across equities, fixed income, derivatives, foreign exchange, and commodities. Core delivery modalities include consolidated data tapes, low-latency streaming protocols, REST and WebSocket APIs, and cloud-native data lake integration. Essential datasets span tick-by-tick prices, end-of-day settlements, security master files for cross-referencing instruments, corporate action processing for dividends and splits, and time-series archives for backtesting. The category has evolved from proprietary terminal-locked content toward unbundled API-first distribution, with growing emphasis on cloud delivery, usage-based pricing, and integration with modern data infrastructure rather than standalone workstations.