ZUG, Switzerland (AP) — Converium Holding AG, a reinsurance company fighting a takeover bid by SCOR SA, said yesterday it is suing the French company and Patinex AG for alleged violations of American securities law.Converium says SCOR unlawfully excluded Converium’s US shareholders, who represent about 22 percent of Converium’s shares, from participating in SCOR’s offer that values the company at about $2.56 billion.

Converium also says SCOR and Patinex — which owns about 12 percent of the voting rights in Converium — failed to make proper disclosures about their purchase of Converium securities. The suit was filed in the US District Court for the Southern District of New York. Converium is seeking a preliminary injunction before May 22, the last date on which Converium shareholders may sell their shares to SCOR, under the terms of the deal SCOR floated this month.

Converium has urged its shareholders to reject the deal.

SCOR said yesterday it had complied with all applicable legal and regulatory provisions in its bid. The company “intends to defend itself vigorously against the unfounded allegations of Converium’s top management”, it said.

Reinsurance companies sell backup coverage to other insurers, spreading risk so the system can handle huge losses from major disasters.