Market Data

Market data is the information generated by trading in financial instruments: last traded prices, bid and ask quotes, trading volume, open interest and the depth of the order book. It is usually grouped into levels, with "level 1" showing the best bid and ask and the last trade, and "level 2" showing the queue of orders at each price. Exchanges sell real-time feeds, often with fees and licence terms, while delayed or summarised data is widely available free. Specialist vendors combine feeds from many venues. In crypto, exchanges publish data through an API, and aggregator websites combine it into rankings by price, volume and market capitalization, identified by each asset's ticker symbol. Data quality varies: crypto volume figures have been distorted by wash trading, so analysts often compare several sources and look at the bid-ask spread and depth as well as reported volume.