$25 billion. Never officially assessed but:
"In domestic affairs, the UAE became involved in a major financial scandal in 1991, when international regulators closed down worldwide operations of the Bank of Credit and Commerce International (BCCI) on fraud and forgery charges. Sheikh Zayed was a founding shareholder of BCCI, and Abu Dhabi businesses and investors lost approximately $2 billion. In December 1993 the government of Abu Dhabi filed a civil suit against BCCI and 13 of its top officials. In July 1994 the former chief executive of the bank pleaded guilty in U.S. federal court to charges of fraud, conspiracy, and racketeering."
http://www.cartage.org.lb/en/themes/GeogHist/histories/history/hiscountries/U/unitedarabeemirates.htmland
"In 1990, when accountants and regulators in the United Kingdom found fraud at BCCI, the Abu Dhabi ruling family and government stepped in again, agreeing to formally buy the bank, assert control, guarantee its losses, replace BCCI's head with the head of its own BCCI affiliate, the Bank of Credit and Commerce Emirates (BCCE), move BCCI's operations and records from London to Abu Dhabi, and work on a plan to find a way to save the bank despite its having acknowledged "mishandling" at least $2.2 billion of Abu Dhabi's money.
By July 5, 1991, when BCCI was closed globally, the Government of Abu Dhabi, its ruling family, and an investment company holding the assets of the ruling family, were the controlling, and official "majority" shareholders of BCCI -- owning 77 percent of the bank. But since the remaining 23 percent was actually held by nominees and by BCCI's alter-ego ICIC, Abu Dhabi was in fact BCCI's sole owner.
After July 5, 1991, it was in Abu Dhabi that most of BCCI's top officials remained, where they remain under the control of the Abu Dhabi government, under conditions said to be luxurious, which the Abu Dhabi government refuses to discuss. While there, they have remained incommunicado, and out of the reach of foreign investigators, unwilling, or unable, to tell the world what happened."
and
** There is some evidence that the Sheikh Zayed may have had a political agenda in agreeing to the involvement of members of the Abu Dhabi ruling family and its investment authority in purchasing shares of Financial General Bankshares, then of CCAH/First American. This evidence is offset, in part, by testimony that Abu Dhabi share purchases in the U.S. bank were done at Abedi's request and did not represent an actual investment by Abu Dhabi until much later.
http://www.fas.org/irp/congress/1992_rpt/bcci/14abudhabi.htmMore on the old crook:
http://www.fas.org/irp/congress/1992_rpt/bcci/14abudhabi.htm