In corporate America, accountants are supposed to play the role of straight man -- keeping businesspeople honest on their financial statements and tax filings.

But according to the U.S. Securities and Exchange Commission, employees of the giant firm KPMG cheated on internal training exams and altered past audit work based on stolen information. 

KPMG agreed to pay a $50 million penalty to settle the charges, the SEC said Monday in a press release.

The accounting firm also agreed to retain an independent consultant "to review and assess the firm's ethics and integrity controls and its compliance with various undertakings."

"KPMG's ethical failures are simply unacceptable," SEC Chairman Jay Clayton said in the press release.

According to an order posted on the regulator's website, former senior members of the firm's Audit Quality and Professional Practice Group "improperly obtained and used confidential information" from 2015 to 2017 belonging to the U.S. government's Public Company Accounting Oversight Board, which the SEC oversees.

"The information obtained included lists of the specific audit engagements the PCAOB planned to inspect, the criteria the PCAOB used to select engagements for inspection and the focus areas of the inspections," according to the release. "The personnel sought the information because the firm had experienced a high rate of audit deficiency findings in prior PCAOB inspections and had made improving its inspection results a priority."

After receiving a confidential list, the KPMG executives then revised audit work papers "to reduce the likelihood that the PCAOB would find deficiencies."

The SEC also said KPMG audit professionals shared exam results on internally administered training courses intended to test whether they understood a variety of accounting principles.   

Steven Peikin, co-director of the SEC's enforcement division, said the "breadth and seriousness of the misconduct at issue here is, frankly, astonishing."

Stephanie Avakian, the other co-director, said the conduct was "particularly troubling because of the unique position of trust that audit professionals hold." 

KPMG, whose U.S. operations are based in New York, said on its website that "we have an ethical culture where everyone embraces a sense of personal responsibility for doing the right thing in the right way."

Ahem. 

Ichiro Kawasaki, a KPMG spokesman, said in an e-mailed comment that "we have learned important lessons through this experience and we are a stronger firm as a result." 

Investors should hope so, since KPMG is one of the "Big Four" accounting firms auditing giant corporations in the Standard & Poor's 500 Index, including Citigroup and General Electric. Both companies needed multibillion-dollar bailouts and debt guarantees from the U.S. government to survive the 2008 financial crisis.