NEW YORK (Bloomberg) ? Institutional investors already claiming securities fraud by Tyco International Ltd. filed a new lawsuit to keep the company from breaking up as planned.

The new suit, seeking class-action status, was filed yesterday in New Hampshire. The plan to split Bermuda-based Tyco, the world?s biggest maker of fire and security systems, into three companies is a fraudulent scheme aimed at shielding assets, the plaintiffs said in a statement.

?The company?s dissipation of assets through the proposed split has been carefully calculated to delay and/or defeat the class?s ability to collect? should the plaintiffs win the securities suit, said the complaint, filed by a group of trade union and pension funds.

Chief Executive Officer Edward Breen announced last month that Tyco will spin off its heath-care and electronics businesses in 2007. Tyco said on January 13 it planned for each new company to share costs including those for litigation. The company has struggled to absorb hundreds of acquisitions made by Breen?s predecessor, L. Dennis Kozlowski, imprisoned for looting Tyco.

The lead plaintiffs include the Plumbers and Pipefitters National Pension Fund, the Louisiana State Employees? Retirement System and Voyageur Asset Management.

?Billionaire financier Carl Icahn said he held 2 million shares of Tyco International Ltd., the conglomerate that plans to split into three publicly-traded companies, at the end of last year.

The stake, which represents less than 0.1 percent of Tyco?s outstanding shares, was valued at $57.7 million, Mt. Kisco, New York-based Icahn Management LP said in a filing with the US Securities and Exchange Commission yesterday.