MONTREAL - Credit monitoring company Equifax says it was hit between mid-May and July by a high-tech heist of sensitive personal information from about 143 million Americans, including an unspecified number of Canadians.

Here are five things you need to know:

1) What is Equifax: The Atlanta-based company is one of three major U.S. credit bureaus that collects personal information such as social insurance numbers that are used by lenders to decide whether to approve financing for homes, cars and credit cards.

2) What is the impact on Canadians: Equifax said hackers may have taken "limited personal information" on an unspecified number of Canadians, but provided no details.

3) Contact information: The company established a website, , where people can check to see if their personal information may have been stolen. Consumers can also call 877-323-2598 for more information. Some people may receive a notice that personal information or credit card numbers were stolen.

4) How to find out if you have been hacked: Check your credit report annually for free from Equifax, Experian, and TransUnion. Check if you have been hacked at: . Reports suggest that people who sign up for TrustedID Premier security service waive their rights to participate in a class-action lawsuit.

5) What to do if your data is hacked:

  • Monitor your existing credit card and bank accounts closely for unauthorized charges. Contact relevant financial institutions, such as banks that issued credit cards and stop cheques, as quickly as possible. Call local police along with Service Canada if you Social Insurance Number was used. Report confirmed cases to the Canadian Anti-Fraud Centre;
  • Change all affected passwords with new, strong and unique passwords for each account;
  • Consider placing a credit freeze on your files. A credit freeze makes it harder for someone to open a new account in your name. It will not prevent a thief from using any of your existing accounts;
  • Consider enrolling in a fraud alert. Equifax says it will offer free identity identity theft protection and credit file monitoring for one year to all U.S. consumers, but doesn't say if that will be available to Canadians. The service monitors if your information is used to open credit accounts or appears on suspicious websites. Several identity theft and recovery companies provide similar services.