NEW YORK (TheStreet) -- Shares of Yahoo! (YHOO) were falling in pre-market trading on Friday after the company confirmed yesterday that more than 500 million accounts on the digital information site were hacked in 2014.

A "state-sponsored actor" stole users' names, telephone numbers, email addresses, birth dates, hashed passwords and, in some cases, security questions and answers, Yahoo said in a company statement.

The company learned of the breach after investigating claims in July that 280 million user account credentials had been put on sale on the black market, sources told Bloomberg.

Yahoo said it is working closely with authorities to resolve the problem.

Additionally, the Sunnyvale, CA-based company agreed in late July to sell its core business to Verizon Communications (VZ) for $4.83 billion. The deal has not yet closed.

Verizon said it was notified of the breach earlier this week, Bloomberg noted.

"We will evaluate as the investigation continues through the lens of overall Verizon interests," the New York-based telecom company told Bloomberg.

Shares of Verizon were edging lower in pre-market trading today.

Separately, TheStreet Ratings objectively rated Yahoo stock according to its "risk-adjusted" total return prospect over a 12-month investment horizon. Not based on the news in any given day, the rating may differ from Jim Cramer's view or that of this articles's author.

TheStreet Ratings rated this stock as a "hold" with a ratings score of C.

The company's strengths can be seen in multiple areas, such as its solid stock price performance, revenue growth and largely solid financial position with reasonable debt levels by most measures. However, as a counter to these strengths, we also find weaknesses including deteriorating net income, disappointing return on equity and feeble growth in the company's earnings per share.

You can view the full analysis from the report here: YHOO

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