The lesson of Arthur Andersen is apparently being applied to Royal Dutch/Shell.

According to the Financial Times, U.S. regulators do not plan to bring charges against the global oil giant for overstating its oil and gas reserves, for 2002 and prior years, by about 23 percent. The concern was that if Shell were convicted and fined, it would result in a further drop in the value of its stock.

According to regulators, however, Shell is being rewarded for voluntarily admitting to the overstatement. “Shell self-reported the material misstatements of its proved oil and gas reserves to the public,” said U.S. Attorney David Kelley, explaining the decision to go easy on the company, according to the report.

He also pointed out that Shell provided “full co-operation” in his investigation, according to the FT, and had agreed to a $120 million civil penalty and “to take substantial remedial actions.” In addition, Kelley cited Shell’s commitment to enhancing the accuracy of its reserves reporting and compliance, and to spend $5 million to develop and implement a comprehensive corporate compliance program.

Perhaps most significantly, however, Kelley acknowledged that criminal prosecution of Shell would have had a “negative effect” on the company’s “innocent employees and legitimate activities.” These concerns have been raised in the aftermath of Arthur Andersen’s prosecution, as critics complained that a very large and influential accounting firm was brought down due to the rogue activities of its Houston office and their audit of Enron Corp.

Last month the Supreme Court overturned Andersen’s conviction.

“We’re aware of the decision taken by the Department of Justice,” Shell spokeswoman Lisa Givert told the FT. “We’re pleased that our cooperation has been appreciated.”

The developments concerning Shell will also be watched closely by Calpine Corp., which is currently being investigated by the Securities and Exchange Commission regarding revisions of its reserves at year-end 2004.