We find that the market capitalization of railroads (SIC 4000) in the CRSP population is 12 percent of the total. We find that the market capitalization of public utilities, including electric, gas, and sanitary services (SIC 4900), as well as communications (SIC 4800) and local and interurban passenger transit (SIC 4100) accounts for 17 percent of the total market capitalization of the CRSP population of companies. The remaining 71 percent is considered to be in industrials. With weights of 45%, 23%, and 32% on industrials, railroads, and utilities, respectively, we can match aggregate market capitalizations with the S&P subsample
