This would be a busy week for any tech CEO: One billion user accounts hacked, and a $4.83 billion deal on the line. Yet we haven’t heard a peep from Yahoo CEO Marissa Mayer.

Yahoo has been the internet's troubled child for the past few years — but things seemed to be looking up after Verizon agreed in July to acquire the company.

And then came a double whammy of data breaches.

Marissa Mayer, who has been at the helm as CEO of Yahoo for the past four years, has largely kept a low profile since the company announced the buyout.

Fast forward to the end of the year, with two mammoth hacks now publicly disclosed and the Verizon deal potentially in jeopardy — and Mayer still hasn't made any statements.

Related: Yahoo Mega-Breach Exposes More Than 1 Billion Accounts

Mayer made her most high-profile appearance in recent times last month at the Glamour Women of the Year Summit. She told the magazine she arrived at Yahoo during a "turbulent period" and learned two key lessons.

"Listening and removing barriers," she said.

And that may be what she's doing right now.

"Marissa and our executive team have been deeply engaged in our ongoing investigation," Yahoo spokeswoman Suzanne Philion told NBC News.

Shuman Ghosemajumder, chief technology officer of Shape Security, a Google Ventures-backed firm, told NBC News one of the reasons Mayer might not be making a statement is because there are still unknowns — such as how the attacker got into Yahoo's systems.

"As CEO, one of the difficulties in issuing any sort of statement is making sure you have enough of the facts so you can portray the situation in the most factual and positive light," he said. "But when you don’t know how the attacker got in, it is difficult to say your systems are protected."

The September breach and the latest one are receiving the "highest attention," and are discussed in daily meetings involving Mayer, her executive team, and chief information security officer Bob Lord, a person familiar with the situation told NBC News. Yahoo is also said to be working closely with a variety of outside experts as it works to answer more questions about the breaches.

And now, Yahoo's deal with Verizon could potentially be in jeopardy.

Related: After Latest Breach, Is Verizon Finally Ditching Its $4.8B Yahoo Deal?

Verizon told CNBC on Wednesday, "As we've said all along, we will evaluate the situation as Yahoo continues its investigation. We will review the impact of this new development before reaching any final conclusions."

But a number of recent reviews on the careers website Glassdoor, purportedly left by employees, suggested uncertainty about the future.

As one person put it, there is "a lot of angst among the ranks."

The Yahoo Mayer Inherited

Mayer is notorious for her work ethic — even building a nursery in her office after a baby and banning employees from telecommuting.

But even that drive hasn't been enough to "roll the rock all the way up the hill" at a company that desperately needed a revival of its core advertising business, Greg Sterling, a contributing editor to Search Engine Land, told NBC News.

"She joined Yahoo at a time when it was almost impossible from a structural standpoint for that company to revive its display [ad] business to the degree that it enjoyed in the past," Sterling said. "Facebook and Google, between the two of them, they really squeezed Yahoo."

Mayer stepped into the CEO position after a period of five years when Yahoo had five CEOs — two of them interim — and when revenue was in decline.

Related: As Yahoo Changes Hands, Marissa Mayer is 'Open Minded'

"I think she was able to bring credibility to the company that it didn't have or was lacking at the time she joined," Sterling said. "After a period of time, I think it became clear she wasn't going to be able to turn the company around and that is when the story sort of changed about her."

Mayer hasn't been afraid to spend big. One of her biggest purchases was three years ago, buying Tumblr for $1.1 billion. She's also signed on big name anchors such as Katie Couric to help attract an audience to Yahoo News.

Hedge funder Dan Loeb was instrumental in plotting Yahoo's resurgence and recruiting Mayer, but reports soon surfaced suggesting the two did not see eye to eye on issues. Loeb sold the majority of his Yahoo stock, making a reported $1 billion, and leaving Mayer fully in control of steering the ship.

Verizon to acquire Yahoo’s operating business - yahoo: Today is a big day for Yahoo! This is the email... https://t.co/Lepxlr44AQ — marissamayer (@marissamayer) July 25, 2016

If the Verizon acquisition is completed, it is unclear how long Mayer would stay on for the transition or what her role would be.

Mayer, who was Google's 20th employee, is 41 years old. She's nowhere near retirement age but could do whatever she wants, given she has an estimated net worth of $300 million — and that's not including any potential package she could get from the Verizon deal.

After the acquisition was announced, Mayer wrote in a Tumblr post, "I'm planning to stay... It's important to me to see Yahoo into its next chapter."

But could a giant pay package change that? In July, Equilar, a compensation data and research firm, estimated Mayer could earn a $57 million golden parachute if Verizon decides to let her go.

Whatever happens, "She'll be seen as the CEO who tried and failed to revive the core business and sold the company," Sterling said. "That will be the headline."