The U.S. Securities and Exchange Commission has laid civil fraud charges against four more former executives of Nortel Networks.

In an expanded complaint released Wednesday, the SEC accused Douglas Hamilton, Craig Johnson, James Kinney and Kenneth Taylor of accounting fraud. They used to be vice presidents of finance for Nortel's optical, wireline, wireless and enterprise business units, respectively.

The U.S. market regulator is seeking civil monetary penalties and also wants to bar the four from being officers or directors of publicly-traded companies.

The SEC is alleging that the four execs were complicit in a fraud to mislead investors about Nortel's true financial state in order to create the appearance of returning to profitability.

"The defendants charged today participated with Nortel's former top executives to improperly maintain, establish and release reserves in order to manipulate earnings and fabricate Nortel's return to profitability in the first quarter of 2003," said SEC enforcement official Christopher Conte in a statement. 

"Nortel's earnings management fraud could not have happened without their efforts," he said. "These defendants all received significant compensation while they were falsifying Nortel's financial results."

Among other things, the SEC is alleging that the four helped turn Nortel's first quarter 2003 loss into a reported profit under U.S. accounting rules by refusing to release tens of millions of dollars in excess reserves, as required by accounting rules, but instead held on to them "for earnings management purposes."

In March, the SEC filed civil fraud charges against former CEO Frank Dunn, former chief financial officer and controller Douglas Beatty, and former controller Michael Gollogly.

In March 2004, Nortel stock plunged after the company warned it would delay filing its audited financial statements for 2003 and would likely make more financial restatements. The company then put its chief financial officer and controller on paid leave. The stock sank again.

Both the SEC and the Ontario Securities Commission began investigations in April 2004 of Nortel's earnings restatements.

On April 28, 2004, Nortel fired Dunn and the two executives who had been on paid leave, and put four more on paid leave.

The company subsequently went through several rounds of accounting restatements as it cleaned up its books.

The OSC alleged in March that Dunn, Beatty, and Gollogly broke securities laws by making "material misstatements" in Nortel’s financial filings that they knew or should have known were "materially misleading."