Al Qaeda in Iraq (AQI) perpetrated terrorist attacks in Amman, Jordan. Injured American nationals and representatives of those killed (plaintiffs) sued HSBC North America Holdings, Inc., and HSBC Bank USA, N.A. (collectively HSBC) (defendants) under the Justice Against Sponsors of Terrorism Act (JASTA). The victims claimed HSBC indirectly aided and abetted the attacks by providing financial services to Al Rahji Bank (ARB), a prominent Saudi bank with known links to AQI and other terrorist organizations. For 25 years, HSBC had provided banking services to ARB. The complaint said HSBC provided nearly $1 billion in funding to ARB, helped it circumvent US regulators, and made conclusory allegations that HSBC meant those funds to go to terrorist organizations. But HSBC had completely ceased doing business with ARB 10 months before the attacks. The trial court dismissed for failure to state a claim. The victims appealed.