Now that Factiva has removed company screening from their "Companies/Markets" pages, Standard and Poor's NetAdvantage probably offers the best option for screening for companies based on financial variables. Start by clicking on the "Companies" tab at the top of the page. From the pull down menu under "Advanced Search", choose either the Corporation Records or the Stock Reports. Both of these titles cover public companies listed in the U.S.
NetAdvantage offers three screening filters. The "Basic" filter includes the commonly used criteria of market cap as well as screens for S&P industry and sub-industry sectors. The "Fundamental" filter allows screening by dividend yield, dividend payout ratio and P/E. The "Financial" filter includes EPS, revenues, net profit margin,return on equity,and return on assets. You can choose variables from any one of the filters or search across all of the filters.
For a simple screening of companies based on either sales or number of employees, use the "Advanced Search" with Standard and Poor's Register of Corporations. In NetAdvantage the Register is divided into "Register-Public Companies" and "Register-Private Companies".