Wells Fargo & Co. said it uncovered nearly 70 percent more potentially unauthorized consumer and small-business accounts than originally thought after an independent investigation into a sales scandal that erupted last year.

The disclosure on Thursday marks the conclusion of that investigation, the bank said. Earlier this month, Wells Fargo CEO Timothy Sloan warned his employees to brace for more negative headlines, saying the review by an outside firm could reveal a "significant increase" in the number of accounts involved.

On Thursday, the bank said the review of 165 million retail accounts opened from January 2009 to September 2016 identified 3.5 million as potentially unauthorized. That is up from the 2.1 million accounts originally identified in a narrower review that only covered 93.5 million accounts opened from May 2011 to mid-2015.

Sloan said on a conference call early Thursday morning that the bank was now focused on remediation for customers, adding that it cast a wide net in the review and that some of the accounts identified may have been opened legitimately.