Oil prices fall amid hopes of US-Iran deal

Oil prices plunged after Qatar said US-Iran negotiations had resumed, and the US treasury secretary suggested a deal could happen "today or tomorrow". These announcements eased concerns over crude supply disruptions that had sent prices soaring in recent months.

The main US oil contract, West Texas Intermediate, dropped five percent to $76.32 a barrel, while the international benchmark Brent North Sea crude fell back below $80 a barrel.

US stocks have also performed well since the market opened this morning, with the Dow Jones up 1.3 percent, and the S&P 500 hitting an interday record for the first time since June.