ITG Broker Edge Universe is a transaction database of nearly 7 million trades ($3.3 trillion in volume) compiled from data contributed by Investment Technology Group Inc. investment manager clients. The information is based on four quarters of U.S. equity trading data for the period ended Sept. 30. Brokers are separated into two categories, core brokers and specialty brokers. Core brokers must: a) trade globally; b) provide trading services in multiple asset classes to include, in particular, exchange-traded equity derivatives; c) provide research; and d) offer soft-dollar and/or commission-sharing agreement services to their clients. Specialty brokers are often used for a specific area of expertise and do not meet all of the above criteria. Ranks are based on the top 50 by dollar volume in each of the two groups. Execution cost is the price difference from order to execution. Value added is the difference between execution cost and the portfolio average execution gain/loss benchmark. Difficulty is based on the dollar-weighted PAEG/L benchmark. Commissions are ranked in cents per share.