How do you find information about businesses that are closed down?

I am trying to do some market research, and need information about similar places that are now closed. How do I go about getting that information. I want to know how long they were opened, etc.How do you find information about businesses that are closed down?the date the company and closed ,if in the USA, will be filed with your states work commission.How do you find information about businesses that are closed down?You may try checking with the commerce department in your city. The company had to have registered to do business in your city. Or try the Better Business Bureau. Or the Attorney Generals office in your state. They may have had other people inquire on the comapny you were looking for.