NBC News reports 360 million newly stolen credentials are for sale on cyber black markets.

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Alex Holden, chief information security officer of Hold Security LLC tells NBC News that his company is not sure where the numbers came from or how they can be used. But he calls the volume of new credentials available "overwhelming."  The credentials could possibly be used to access online bank accounts, health records or any other computer system.

He believes the breaches have yet to be publicly reported because it often takes a third party to confirm. Holden's company will notify the companies involved. One breach, according to Holden, could be the largest known with 105 million records compromised.

Holden tells Computerworld the large number of breached accounts indicates a shift in the tactics of hackers by targeting large collections of information rather than individuals.

Hold Security helped Adobe uncover a breach in October, 2013 of millions of encrypted passwords.

Adam Levin, chairman and founder of Identity Theft 911 says consumers can protect themselves by carefully monitoring all of their credit card accounts. “Consumers have to check their accounts, their credit card accounts, their debt card accounts on a daily basis to make absolutely sure that every transaction they see is yours.”

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David Matthau contributed to this report