SAN FRANCISCO — Wells Fargo may have opened as many as 3.5 million bogus bank accounts without its customers’ permission, attorneys for customers suing the bank have alleged in a court filing, suggesting the bank may have created far more fake accounts than previously indicated.

The plaintiffs’ new estimate of bogus bank accounts is about 1.4 million, or 67 percent, higher than the original estimate — disclosed last year as part of a settlement with regulators — that up to 2.1 million accounts were opened without customers’ permission.

In estimating the higher number of fake accounts, the plaintiffs’ attorneys examined a much longer time period than regulators and the bank had previously addressed, they said in court documents. The attorneys covered a period from 2002 to 2017, rather than the previously scrutinized five-year stretch from 2011 to some time in 2016 in which the bank acknowledged setting up unauthorized accounts. Scrutiny of bank employees’ activity during that five-year period led to the settlement last September, which required the bank to pay $185 million in fines.

The plaintiffs’ attorneys described how they developed the new, higher estimate of the bank’s number of bogus accounts: “Public information, negotiations and confirmatory discovery” were the primary sources used to arrive at the new estimate, the court documents stated.

“It’s important to note that these are estimates from the attorneys for the plaintiffs,” said Ruben Pulido, a spokesman for San Francisco-based Wells Fargo.

The 3.5 million figure is based on a “hypothetical scenario” and remains unverified, Pulido stated.

“The number of unauthorized accounts estimated in the filing do not reflect actual unauthorized accounts,” Pulido said. “The number is the plaintiffs’ estimate — and only an estimate.”

The plaintiffs also acknowledged the estimate of 3.5 million accounts could turn out to be greater than the actual number of bogus accounts created, saying in court records, “This number may well be over-inclusive.”

Wells Fargo’s Chief Executive Officer Timothy Sloan told investors during a meeting Thursday in San Francisco that 2016, the year when the bogus-accounts scandal surfaced, was challenging for the bank.

“There is no question that 2016 was among the toughest in our 165-year history,” he said.

Sloan acknowledged that the bank had lost its way.

“It’s clear that we had an incentive program and a high-pressure sales culture within our community bank that drove behavior that many times was inappropriate and inconsistent with our values,” Sloan told the investors.

Wells Fargo terminated 5,300 employees due to their connection with the opening of unauthorized checking or credit accounts. John Stumpf, the former Wells Fargo CEO who presided over the high-pressure culture at the bank, resigned. Carrie Tolstedt, who led the community bank at the height of the accounts fiasco, also left the bank.

Eventually, Wells Fargo rescinded $69 million in pay for Stumpf and $66.3 million in pay for Tolstedt as punishment for their roles in the scandal, according to the most recent court filings.

Wells Fargo shares dropped 1.3 percent Friday and closed at $53.02. So far in 2017, its shares have fallen 3.8 percent. The S&P Bank Index is down 3 percent over the same period.

The new administration of President Donald Trump could scrutinize Wells Fargo with fresh eyes, which could extend the process of resolving the scandal and its fallout, said Ken Thomas, a Miami-based independent banking analyst.

“It’s not over by a long shot for Wells Fargo,” Thomas said.