The crash followed an asset bubble. Since 1922, the stock market had gone up by almost 20 percent a year. Everyone invested, thanks to a financial invention called buying "on margin." It allowed people to borrow money from their broker to buy stocks. They only needed to put down 10-20 percent. Investing this way contributed to the irrational exuberance of the Roaring Twenties.
On September 16, 2008, failures of massive financial institutions in the United States, due primarily to exposure to packaged subprime loans and credit default swaps issued to insure these loans and their issuers, rapidly devolved into a global crisis. This resulted in a number of bank failures in Europe and sharp reductions in the value of stocks and commodities worldwide. The failure of banks in Iceland resulted in a devaluation of the Icelandic króna and threatened the government with bankruptcy. Iceland obtained an emergency loan from the International Monetary Fund in November. In the United States, 15 banks failed in 2008, while several others were rescued through government intervention or acquisitions by other banks. On October 11, 2008, the head of the International Monetary Fund (IMF) warned that the world financial system was teetering on the "brink of systemic meltdown".
On Black Monday, the Dow Jones Industrial Average fell 38.33 points to 260, a drop of 12.8%. The deluge of selling overwhelmed the ticker tape system that normally gave investors the current prices of their shares. Telephone lines and telegraphs were clogged and were unable to cope. This information vacuum only led to more fear and panic. The technology of the New Era, previously much celebrated by investors, now served to deepen their suffering.
The Dow was already down 20 percent from its September 3 high, according to Yahoo Finance DJIA Historical Prices. That signaled a bear market. In late September, investors had been worried about massive declines in the British stock market. Investors in Clarence Hatry's company lost billions when they discovered he used fraudulent collateral to buy United Steel. A few days later, Great Britain's Chancellor of the Exchequer, Philip Snowden, described America's stock market as "a perfect orgy of speculation." The next day, U.S. newspapers agreed.
It’s likely some of these Americans might rethink pulling their money if they knew how quickly a portfolio can rebound from the bottom: The market took just 13 months to recover its losses after the most recent major sell-off in 2015. Even the Great Recession — a devastating downturn of historic proportions — posted a complete market recovery in just over five years. The S&P 500 then posted a compound annual growth rate of 16% from 2013 to 2017 (including dividends).
Having been suspended for three successive trading days (October 9, 10, and 13), the Icelandic stock market reopened on 14 October, with the main index, the OMX Iceland 15, closing at 678.4, which was about 77% lower than the 3,004.6 at the close on October 8. This reflected that the value of the three big banks, which had formed 73.2% of the value of the OMX Iceland 15, had been set to zero.