They have presumably gone out of business. Another 141 companies included in the MIT database are known to have ceased operation. In 55 cases, one company in the MIT family has since been acquired by another company in the family. Since our analysis includes total employment of large corporations, regardless of location, we have eliminated these 55 companies to avoid double counting employment and sales. Keeping Track of Company Changes Following a group of companies over time is no easy task.
Companies change addresses, phone numbers, and even company names.
Companies are sold to other companies and may or may not retain their original name and corporate identity. Table A2 gives summary information on the 3,998 active firms in the MIT database. To simplify the presentation, companies are grouped by region and industry. The definitions are consistent between the company database and the founder survey and are presented here. The regions used to aggregate U.S. companies are shown in Map A1.