Wells Fargo's fake accounts scandal was in fact much bigger than originally revealed, a new analysis released by the bank Thursday showed.

After completing a third-party review of the bank's practices of setting up accounts for customers they didn't want, the bank said that there were up to 3.5 million such accounts created between 2009 and 2016 — two-thirds more than the 2.1 million originally reported.

Thursday's revelation is the latest in a long string of bad news for the mega-bank, which has already seen major fallout from the fake accounts scandal that first rose to the attention of Congress last fall.

Already, the company's CEO and other executives have had to step down after grilling by Congress and the threat of regulatory and legal action, in addition to the $100 million in regulatory fines initially applied in September.

Those actions have failed to mollify the bank's congressional critics, who have only increased scrutiny of the bank and its board following subsequent revelations about its practices. Most recently, for instance, Democrats have called for a new round of hearings related to the news that the bank charged 800,000 customers for auto insurance they didn't need.

In particular, Sen. Elizabeth Warren, D-Mass., has lobbied the Federal Reserve to remove members of Wells Fargo's board who were there during the scandal. Warren reiterarted that call Thursday.

The tally of fake accounts rose in part because the third-party review found more accounts from the original time period, and because it reviewed more years.

In a statement, CEO Tim Sloan called the review an "important milestone" in making amends to customers, and said that "we apologize to everyone who was harmed by unacceptable sales practices that occurred in our retail bank."

On CNBC, personality Jim Cramer lit into the bank, saying that "it's rogue. This is a rogue bank."