Verizon Communications, the company that bought over Yahoo, has revealed that all 3 billion of its accounts were hacked in a cyber attack that rocked the company in 2013.

According to Reuters, the new development triples the number of Yahoo accounts that was initially thought to have been affected by the attack, described as the largest data breach in history.

It also increases the number of lawsuits that could be filed by Yahoo shareholders and account holders against Verizon, Yahoo’s new owners.

The company faced at least 41 consumer class-action lawsuits in US federal and state courts, in May.

John Yanchunis, a lawyer representing some of the affected Yahoo users, said a federal judge had asked for more information to justify his clients’ claims.

“I think we have those facts now,” he said. “It’s really mind-numbing when you think about it.”

Last December, Yahoo said that data from more than 1 billion accounts was compromised in 2013, forcing it to cut the price of its assets in a sale to Verizon.

But in a statement on Tuesday, the company said “recently obtained new intelligence” revealed that all user accounts had been affected.

It however said that the investigation indicated that the stolen information did not include passwords in clear text, payment card data, or bank account information.

But experts said the hacked data included security questions and backup email addresses, which could make it easier to break into other accounts held by the users.

Many Yahoo users have multiple accounts, so the actual number of people affected was far fewer than 3 billion.

A Yahoo official emphasized that the 3 billion figure included many accounts that were opened but never, or only briefly, used.

The company said it was sending email notifications to additional affected user accounts.