Oil prices roared to a fresh record above $147 a barrel on Friday. But as momentous as the fact that the price is now threatening to reach the $150 landmark has been the extraordinary volatility in prices.

US crude on Tuesday recorded its largest one-day dollar decline – $5.33 a barrel – since the start of the first Gulf war in January 1991. Thursday saw the second largest one-day dollar gain – $5.60 – since crude futures started trading in the 1980s, forcing any bears who were rash enough to bet on a deeper correction to close out their short positions.