Parmalat had induced U.S. investors to purchase bonds and notes totaling approximately $1.5 billion. In addition, in August 1996 Parmalat sponsored an offering of American Depositary Receipts (ADRs) in the United States, with Citibank, N.A., headquartered in New York City, as depositary. Parmalat actively participated in the establishment of the ADR program. This activity made Parmalat subject to SEC rules. The SEC’s inquiries focused on up to approximately €1.05 billion ($1.5 billion) of notes and bonds issued in private placements with U.S. investors. The banks investigated included Bank of America, JP Morgan Chase, Merrill Lynch, and Morgan Stanley Dean Witter. Parmalat’s administrator, Enrico Bondi, helped the authorities identify all the financing transactions undertaken by Parmalat from 1994 through 2003. During the investigation, it was noted that Parmalat’s auditor from 1990 to 1999, Grant Thornton, did not have copies of crucial audit documents relating to the company’s Cayman Islands subsidiary, Bonlat. The emergence of a €5.16 billion (approximately $7.28 billion) hole at Bonlat triggered the Parmalat collapse. The accounting firm has since handed over important audit documents to investigators.