Abu Dhabi’s sovereign wealth fund has already lost twice in its case against Citigroup over a massive 2007 investment deal gone sour. But with more than $4 billion on the line in the dispute, the Abu Dhabi Investment Authority is taking its fight to the U.S. Court of Appeals for the Second Circuit. Quinn Emanuel Urquart & Sullivan partners Peter Calamari and David Elsberg filed a notice of appeal on March 22 in federal court.

Southern District Judge George Daniels (See Profile) dismissed ADIA’s case on March 4, ruling for Citi and its lawyers at Paul, Weiss, Rifkind, Wharton & Garrison. Abu Dhabi Investment Authority v. Citigroup, 12 Civ. 283, stemmed from ADIA’s 2007 decision to invest $7.5 billion in Citi just as the global economy was tanking. The fund sued in federal court to overturn a decision by International Centre for Dispute Resolution arbitrators, who concluded in October 2011 that ADIA couldn’t prevail on its claims that Citi duped the fund into making the deal and breached the parties’ investment agreement. In an 18-page decision Daniels rejected arguments by ADIA’s lawyers that the arbitration panel botched key rulings, leaving ADIA unable to adequately present its case.

ADIA invested $7.5 billion in Citi in November 2007, just as the global economy was beginning to show serious strains. According to reports at the time, Abu Dhabi’s royal family hoped to take advantage of market dislocation and a weak dollar, while Citi was eager for a big capital infusion. ADIA’s timing couldn’t have been much worse. The financial crisis quickly deepened, and by 2009 Citi shares that the fund calculated would be worth more than $30 apiece were trading below $4 a share.

Brad Karp, Leslie Gordon Fagen and Daniel Toal, partners at Paul Weiss, are representing Citi.