The Wells Fargo fake account scandal has sparked a search by federal regulators for bad behavior at other big U.S. banks.
The Office of the Comptroller of the Currency fired off letters to most large and midsize banks asking for information about their sales practices and incentive systems, a spokesman for the OCC confirmed to CNNMoney.
The OCC, the nation's chief bank regulator, said the review began this month and is focused on employees are incentivized to sell banking products.
The process will include on-site reviews of the banks and is being conducted in coordination with other federal bank regulators, including the Federal Reserve, the FDIC and the Consumer Financial Protection Bureau.
The OCC said the extra scrutiny was triggered by the Wells Fargo fake account scandal. Thomas Curry, head of the OCC, told U.S. senators at last month's Wells Fargo hearing his agency would investigate whether other banks employed high-pressure sales tactics that led to fake accounts.
"Banks are under enormous margin pressure. That could be a bad environment," Curry said at the time.
Related: 'Wells Fargo isn't the only one'
Wells Fargo (WFC) set off shockwaves in early September when it admitted to creating as many as 2 million fake accounts, which led to the firing of 5,300 employees since 2011.
But Wells Fargo employees blame an extremely intense sales culture and unrealistic sales goals at the bank for the scandal. Wells has since abandoned those goals.
But the scandal raised questions of how widespread the practices were and whether other banks were opening unauthorized accounts as well.
In fact, nearly a dozen current and former employees at large and regional banks such as Bank of America, Citizens Bank, PNC (PNC) and SunTrust (STI) have told CNNMoney that a sales obsession pervades their banks too. They describe immense pressure to get customers to open multiple accounts.
The OCC declined to reveal which banks received the letters, saying only that most large and midsize lenders will be involved.
JPMorgan Chase (JPM), Bank of America (BAC), Citigroup (C) and Santander (SANPRA) were among the banks that the OCC has sent letters to, according to The Wall Street Journal, which first reported news of the review.
A Chase spokesperson said the bank doesn't discuss specific conversations with regulators. However, Chase confirmed it would expect to be included in any industry-wide review like the OCC one.
Citi declined to comment, while Bank of America did not respond to requests for comment. A spokesperson for Santander said the bank is "not at liberty to confirm or comment."
Related: Wells Fargo workers describe mental health nightmares
So far, none of the big banks have admitted to uncovering widescale problems like what was discovered at Wells Fargo.
Earlier this month, JPMorgan told reporters a "deep dive" of its own consumer business revealed some isolated incidents of "cross-selling issues" but no systemic problems.
Some regulators have expressed concern over the long-term impact of bad behavior at banks.
William Dudley, president of the New York Federal Reserve, warned last week that "deep-seated cultural and ethical problems have plagued" the industry in recent years. "This has eroded the industry's trustworthiness."
Consumers are responding, too. One in three Wells Fargo customers are actively exploring leaving the bank, according to a post-scandal survey by consulting firm cg42 .
--CNNMoney's Paul R. La Monica and Patrick Gillespie contributed to this report
