This dataset contains standardized data for blockholders of 1,913 companies. The data was cleaned from biases and mistakes usually observed in the standard source for this particular type of data. Blockholders’ data is reported by firm for the period 1996-2001. The data cleaning procedure is explained in detail by Jennifer Dlugosz, Rudiger Fahlenbrach, Paul A. Gompers, and Andrew Metrick in their study “Large Blocks of Stocks: Prevalance, Size, and Measurement”.
Available through: WRDS