<P> A financial data vendor provides market data to financial firms, traders, and investors . The data distributed is collected from sources such as a stock exchange feeds, brokers and dealer desks or regulatory filings (e.g. an SEC filing). </P> <P> Financial data vendors have been in existence as long as financial data has been available . Financial data includes "pre-trade" such as bid / ask data necessary to price a financial instrument and post-trade data such as the last trade price and other transaction data . </P>

Which information service provides market share information for an investor