If you subscribe to get NYSE data, you literally get everything that trades there. You're not likely going to need all those names running through your simulator. I removed all the nonsense that I knew I didn't want to be in. I called that process "raking the data." I removed the following from the data feed: -stocks below $20 per share -stocks above $100 per share -shares with less than 1 million ADTV -Preferred Stock You can figure out what is best for you. What is left is what you will run through your simulator. This also helps you stay objective and can stop you from obsessing about one particular name. Also, it's fantastically hard at best to keep track of all the potential names to trade. This process can help you stay open-minded.