Quandl is a numerical data distribution platform that offers access to several million financial, economic and social datasets.
Quandl indexes data from multiple sources allowing users to find and download in various formats. All Quandl's data are accessible via an API. API access is possible through packages for multiple programming languages including R, Python, Matlab and Stata. Data access is allowed via an Excel add-in .
PortfolioEffect Volatility and Risk Factors Database on Quandl provides EOD risk estimates using high frequency market data for over 8,000+ US Equities.