For some research purposes, I need the official s&p500 companies list. I cannot use any data from Wikipedia or any other such kind of websites. I can use data from yahoo finance or s&p500 official websites. I got historical data from yahoo finance but I couldn't find any data for S&P500 companies list there. Can anybody suggest a reliable source to get the S&P500 companies list?
The WRDS/CRSP dataset has that data available. But you need to pay to access it:
Historical constituents are in the (SAS) sets dsp500list and msp500list. It contains the start and ending date for each security (identified by PERMNO). Prior to March, 1957, the index contains 90 issues. Currently, they are only available in our UNIX server. According to CRSP methodology, for a security to be included in the CRSP Indexes for the S&P 500 Universe, it must have a price at the end of the current period, a price at the end of the previous period, and it must be a member of the S&P 500 Universe at the end of the current period.