San Francisco

YAHOO on Tuesday said that all 3 billion of its accounts were hacked in a 2013 data theft, tripling its earlier estimate of the size of the largest breach in history, in a disclosure that lawyers said sharply increased the legal exposure of its new owner, Verizon Communications Inc.

The news expands the likely number and claims of class action lawsuits by shareholders and Yahoo account holders, they said. Yahoo, the early face of the Internet for many in the world, already faced at least 41 consumer class-action lawsuits in US federal and state courts, according to company securities filing in May.