BCCI was a bank started in 1972 that was used by the CIA and helped fund groups like Osama bin Laden. It engaged in money laundering and catered to criminal clients. It had over $20 billion in assets making it one of the largest private banks. However, it used complex structures across 70 countries to avoid regulation. This included unusual accounting practices designed to frustrate investigators. It was eventually shut down in 1991 after audits revealed its criminal activities.