Hi there. I'm trying to find a (hopefully free) source of historical data for constituents of major indexes, primarily S&P 100, 400, 500, 600, 900, 1500. I know I can get the latest from S&P site itself, however I need to know what was in those indices at a particular time in the past (for at least the past year, although further back in time would be great). Does anyone know where I might obtain this information? Or maybe someone has kept track and would be kind enough to share? Thanks in advance.