Houston ? Three former Dynegy Inc. executives were charged in a federal indictment unsealed Thursday with conspiracy and fraud for their roles in accounting transactions that regulators said improperly boosted the energy company’s cash flow by $300 million and cut its taxes.

“These defendants are accused of withholding the truth about Dynegy’s true fiscal condition from the SEC, shareholders and the public,” U.S. Atty. Michael Shelby said.

Named in the indictment were Jamie Olis, 37, Dynegy’s former senior director of tax planning; Gene Shannon Foster, 44, former vice president of tax; and Helen Christine Sharkey, 31, a member of Dynegy’s risk control and deal structure group.

Each is charged with conspiracy, securities fraud, mail fraud and wire fraud.

The Securities and Exchange Commission also filed a civil lawsuit naming the three.

Dynegy released a statement saying it remained “committed to complete cooperation” with the U.S. Attorney’s office in Houston and other governmental agencies.

Helen Christine Sharkey, left, a former member of Dynegy's risk control and deal structure group, is escorted into the federal courthouse in Houston. Sharkey is one of three former Dynegy Inc. executives charged in a federal indictment that was unsealed Thursday.

“Dynegy has been, and will continue to be, committed to restoring the confidence of all stakeholders,” it said.

In September, Dynegy agreed to pay the SEC $3 million to settle the commission’s investigation of a natural gas deal that improperly boosted the company’s reported cash flow. The government alleges Olis, Foster and Sharkey created the deal to make Dynegy’s books look better and deliberately kept it from auditors at Arthur Andersen.

The SEC determined the project a complex series of accounting transactions related to a contract with ABG Gas Supply LLC increased Dynegy’s reported cash flow by $300 million. The SEC said that the $300 million should have been identified as financing rather than cash flow on Dynegy’s annual filing for 2001 and that the company overstated net income to cut its taxes by $79 million.

Dynegy agreed to the SEC’s terms without admitting or denying the agency’s findings, and it restated its finances. It was one of several energy companies being investigated by the SEC over trading and accounting practices.

Dynegy is still under investigation by California power regulators who found that a series of blackouts that plagued the state in 2000 and 2001 could have been avoided if generators had not withheld electricity at crucial times. The California Public Utilities Commission named the five largest non-utility power generators, including Dynegy.

Last fall, Dynegy announced that it was dumping its struggling energy trading business in the wake of the Enron scandal. It is still in the business of power generation, natural gas liquids, regulated energy delivery and communications.