Try one of following databases:
- MarketLine Advantage: Gives top competitors of a specific company as well as the top competitors in the industry.
- Mergent Online or Mergent Horizon. Note that Mergent Horizon only has public companies. Mergent Horizon is a more complex database but it has more information. It is a separate tab within Mergent Online.
- Nexis Uni: Lists top competitors but you could also create a list of companies looking for similar characteristics like SIC or NAICS codes.
- ReferenceUSA: Gives a competitors report, but not always comprehensive. However, it too allows you to create a list by codes or other characteristics. It is best for local companies.