On December 1, 2015, in OBB Personenverkehr AG v. Sachs, the US Supreme Court held that because the plaintiff's personal injury suit was not "based upon" the sale of a Eurail pass, but on the defendant's conduct where the injury occurred, the suit did not fall within the commercial activity exception to the Foreign Sovereign Immunities Act (FSIA) and the defendant was immune from suit in the US ( (S. Ct. Dec. 1, 2015)).

Carol Sachs, a California resident, purchased a Eurail pass over the internet from a Massachusetts-based travel agent. During her travels in Europe, Sachs fell onto the tracks at the Innsbruck, Austria train station. OBB Personenverkehr's (OBB) moving train crushed her legs, both of which had to be amputated. Sachs filed suit against OBB in the US District Court for the Northern District of California. Because OBB is an Austrian state-owned railway, it claimed sovereign immunity under the FSIA, which is the sole basis for obtaining jurisdiction over a foreign state in US courts, and moved to dismiss for lack of subject matter jurisdiction. Although both parties agreed that OBB qualified as a foreign state for purposes of the FSIA, and was presumptively immune from suit in the US, Sachs argued that her suit fell within the FSIA's commercial activity exception, which provides that a foreign state does not have immunity when the action is "based upon" a commercial activity carried on in the US by the foreign state.

The district court found that Sachs's suit did not fall under this exception and dismissed the case. The US Court of Appeals for the Ninth Circuit initially affirmed but ordered a rehearing en banc and subsequently reversed. There, the en banc majority found that Sachs's claims were "based upon" the sale of the Eurail pass in the US because the sale provided "an element" of Sachs's claims and therefore the suit fell within the commercial activity exception.

The Supreme Court reversed, finding that Sachs's suit was not "based upon" the sale of the Eurail pass for purposes of the FSIA commercial activity exception but on the incident in Austria. The court rejected the Ninth's Circuit's approach as incompatible with its decision in Saudi Arabia v. Nelson, which provided guidance on the "based upon" inquiry (507 U.S. 349 (1993)). Under Nelson, the mere fact that the sale of a Eurail pass would establish a single element of a claim was insufficient to demonstrate that the claim was "based upon" that sale for purposes of the commercial activity exception. Instead, an action is "based upon" the particular conduct that constitutes the gravamen of the plaintiff's suit.

The Court therefore looked at the core of the suit and concluded that the gravamen plainly occurred at the Austrian train station, where the tragic episode occurred, and not when Sachs purchased her pass. Any other approach would permit plaintiffs to evade the FSIA's restrictions through artful pleading. As a result, Sachs's suit fell outside the commercial activity exception, OBB had sovereign immunity under the FSIA, and US courts lacked jurisdiction over the suit.