Which 2008 crisis caused Iceland's three major commercial banks to collapse within days?

The 2008–2011 Icelandic financial crisis caused Iceland's three major commercial banks to collapse within days.

Glitnir, Landsbanki, and Kaupthing had expanded rapidly after Iceland's banking sector was deregulated. Their balance sheets became enormous compared with Iceland's economy, and they relied heavily on international wholesale funding. When global credit markets froze during the 2008 financial crisis, refinancing that debt became impossible.

The Icelandic government took control of Glitnir on September 29, 2008, Landsbanki on October 7, and Kaupthing on October 9. The collapse drove the Icelandic króna sharply lower and caused the country's stock exchange to suspend trading temporarily.

The crisis is often described simply as Iceland's banking collapse, but it also involved currency weakness, emergency capital controls, a recession, and later political controversy. It was closely connected to the global financial crisis but had distinctly Icelandic causes, especially the oversized banking system.