Global markets climbed and the price of oil fell after Hosni Mubarak stepped down as president of Egypt on Friday.
There had been concerns that almost 18 days of anti-government protests could have spread across the region and added to market volatility.
But analysts said that Mr Mubarak's resignation had made Egypt's political future a little clearer, boosting investor sentiment.
Oil was trading higher earlier in the day, but fell after the announcement was made in Cairo.
While not a major oil producer, Egypt controls the Suez Canal, a major route for oil tankers and cargo ships.
The BBC reports that investors have been worried that unrest in Egypt could spread to nearby oil-producing nations, disrupting supplies.
US light sweet crude lost $US1.12 to $US85.61 per barrel. In London, Brent crude fell 31 cents to $US101.13 p/b.
On Wall Street, the Dow Jones index rose 43.97 points, 0.4%, to 12,273.3 on Friday, its highest close since June 2008.
The Nasdaq index rose 0.7% to 2,809.4 points.
In London, the FTSE 100 finished 0.7% higher at 6,062.9 points. The CAC-40 in Paris and the DAX in Frankfurt also had late surges.