Williams v. Costco Wholesale Corp.

Williams sued Costco in California state court, alleging violations of federal and state law. Costco properly removed the case to district court, relying on federal question jurisdiction. After removal, Williams amended his complaint to eliminate the only federal claim and to add new state law claims. He then filed a motion to remand. The district court held that it had discretion to remand the state law claims, and did so.

At the time Williams filed his motion to remand, however, the district court had jurisdiction over the remaining state law claims based on diversity of citizenship. The district court recognized this, but held that Costco could not rely on this ground because it had not filed a second removal notice within 30 days of the amended complaint — the document that had first made it clear that the requirements for diversity were satisfied.

The district court erred. We have long held that post-removal amendments to the pleadings cannot affect whether a case is removable, because the propriety of removal is determined solely on the basis of the pleadings filed in state court. See Sparta Surgical Corp. v. Nat’l Ass’n of Sec. Dealers, Inc., 159 F.3d 1209, 1213 (9th…