Freeport-McMoRan Inc. v. K N Energy, Inc.

Background

McMoRan Oil and Gas Company and its parent, Freeport-McMoRan, sued K N Energy, a Kansas energy company, in federal court over unpaid natural gas payments. At filing, the plaintiffs and defendant were citizens of different States, so the case relied on federal diversity jurisdiction. After the suit began, McMoRan transferred its contract rights to FMP Operating Company, a limited partnership whose partners included citizens of Kansas and Colorado. Plaintiffs asked to add FMPO as a party to reflect that transfer; the district court allowed FMPO to be added but kept McMoRan in the case. The district court ruled for the plaintiffs, but the Court of Appeals dismissed the suit, saying the addition of FMPO destroyed diversity jurisdiction.

Reasoning

The central question was whether a later addition of a nondiverse party strips a federal court of diversity jurisdiction when diversity existed at filing. The Court explained that citizenship for diversity is measured when the lawsuit starts. It said Carden dealt with when the original plaintiff itself was a limited partnership and did not change the time-of-filing rule. The Court relied on earlier decisions that once jurisdiction exists it is not lost by later events. Because FMPO had no interest at filing and was not essential then, adding it later did not destroy jurisdiction. The opinion also noted that another case, Owen, did not overturn this basic rule.

Real world impact

The ruling lets federal diversity cases continue when complete diversity existed at the start, even if a nondiverse party joins later. Businesses can transfer interests during litigation without automatically forcing dismissal. The decision removes a procedural risk that might otherwise discourage ordinary commercial transactions during lawsuits.