U.S. stocks are down: Markets were already wobbling ahead of the flash crash of May 6, when the Dow plunged nearly 1,000 points during its worst intraday session ever. Since then, stocks have zigzagged, with the Dow posting a series of triple-digit swings as investors struggle to find their footing.

Since peaking at 17-month highs in late April, the Dow has lost 6% and the broader S&P 500 has lost 8%. The Nasdaq reached a 22-month high in late April and has since fallen 9%.

European and Asian stocks are down: Global markets have had it even worse than markets in the United States. The British FTSE 100 is down 10% since late April, the French CAC 40 is down 12% and the German DAX is off 5%.

The Shanghai Composite index has lost nearly 15% in the last month, briefly entering bear territory, while the Japanese Nikkei has lost 10%. Asian markets have been hammered by the European crisis and the euro's weakness too, but the region has concerns of its own. Higher inflationary pressure in China is causing the government to slow down the pace of growth and some investors are worried they'll take it too far. Japan's economy grew in the first quarter, but less than expected, adding to the pressure.

Volatility is rising: After a relatively calm period following the 2008-early 2009 whiplash, volatility has returned.

Wall Street's fear factor, the CBOE Volatility index (the VIX), closed at a 13-month high of $40.95 two weeks ago and has seesawed since then. Currently it stands in the mid-30s, up 125% from the three-year low of $15.58 it hit in mid-April.

Bonds still buoyant: Investors are flocking to bonds, seen as a safe spot to park their cash in times of economic uncertainty. A month ago, the yield on the 10-year note was nearing 4%, sparking concerns that a period of higher rates would hurt the still-germinating housing market recovery. Not so now.

The yield on the 10-year currently stands at 3.35% and experts expect it to keep falling. (As bond prices rise, the corresponding yields fall).

Gold rising, oil slipping: Investors worldwide have been buying up gold as a safe-haven alternative to the battered euro but also as a hedge against inflation. Gold closed at a record $1,243.10 an ounce last week. It's backed off since then and some analysts think it could be in for a major plunge in the next two years.

Meanwhile, oil, copper and other commodity prices have been falling on worries about the global economy.

Other factors: Bank-to-bank lending rates have been on the rise, including Libor, the London Interbank offered rate. 3-month Libor edged up to 0.48% Wednesday from 0.31% a month ago. However, Libor rates remain far below the 10-year high of 3.77% hit in late September 2008 at the height of the crisis.