Concord, N.H. ? Tyco International Inc. used aggressive accounting to inflate financial results by nearly $400 million this year, but an exhaustive internal review found no “systemic or significant fraud,” the company said Monday.

In a long-awaited report to the Securities and Exchange Commission, the diversified manufacturing conglomerate said several accounting errors had been found and corrected, but that they were not material to the company’s overall finances.

The report described a pattern of aggressive accounting by former management with the purpose of increasing reported profits. The tactics included pressuring and inducing midlevel managers to increase earnings by choosing more aggressive accounting policies.

As a result of the accounting errors, the company overstated its financial results by a total of $382.2 million in 2002, the report said.

Tyco reported a net loss of $9.1 billion on revenues of $35.7 billion in the fiscal year that ended Sept. 30.

The pretax adjustment comes on top of a previously announced $2.8 billion in charges for the year. Tyco’s accounting is under review by the SEC and several former top executives face criminal charges of fraud and corruption.

The investigation was conducted by the law firm of Boies, Schiller & Flexner LLP and the forensic accounting firm of Urbach Kahn & Werlin.

Based in Bermuda but with U.S. headquarters in Exeter, Tyco makes everything from telecommunications equipment to home alarm systems.

Its stock dropped sharply early this year when the company announced, and then rescinded, a breakup plan. In June, then-chief executive Dennis Kozlowski resigned a day before being indicted on charges of evading New York sales tax on art purchases.

He and former chief financial officer Mark Swartz face criminal charges for allegedly stealing millions of dollars from the company.

In a preliminary report to the SEC in September, the company said it had found millions of dollars in unauthorized payments to dozens of employees, including Kozlowski. It accused Kozlowski of trying to thwart an investigation of the payments.

Kozlowski and Swartz have pleaded innocent to all charges