Do you shop? You may be at risk.

INDIANAPOLIS (WISH) - If you own a computer, hackers likely got some valuable information about you over the weekend. Armed with this information, they may try to tap into your computer or steal your identity.

This was no ordinary data breach. Customers of 50 major companies have been exposed, their email addresses stolen. You probably are among those who have been notified by one of those companies. Best Buy, Target and Chase Bank are just a few of the companies sending warnings to their customers.

"Everybody who is an American consumer is going to get one of those emails," said Damon Richards, a computer expert who runs an IT consulting firm in Indianapolis.

The breach occurred not at the 50 individual companies, but at a company called Epsilon, which manages customer emails for the companies involved, Richards said says the Epsilon breach is big.

"They do 40 billion emails a year that they send out on behalf of lots and lots of major merchants," he said.

Hackers obtained only e-mail address for customers, and the knowledge that you do business with a particular company. But, Richards said, that can be enough for them to seem official.

"From that, I can convince you that I am sending you legitimate email from that merchant, and that's the risk," he said.

So you should be particularly skeptical of any communications from the affected companies, said Dr. Darrell Bowman, assistant professor of information systems at the University of Indianapolis.

"If you do not recognize the individual, if the status line or the subject line doesn't look like something that is legitimate, definitely don't open the email," he said.

Bowman said legitimate companies never ask you for your password or log-in information – they already have it.

And if there’s a link inside an email from these companies, don't click on it. If you do, you could give access to hackers or unleash a virus in your computer.

If you do receive a suspicious email, just delete those it, or pick up the phone and call the company and do business over the phone, not online.