U.S. oil futures have rocketed up 18% over the past three weeks, sparked by escalating concerns about Iran.

The surge has outstripped advances for most other assets. Stocks and copper -- which, like oil, are strongly tied to economic growth expectations -- have seen much smaller gains. The Standard & Poor's-500 Index has increased 2.5% over that span, while Comex copper futures have climbed 3%.

But neither stocks nor copper are as dependant as oil on the Persian Gulf's Strait of Hormuz. Approximately 20% of the world's crude oil passes through the 24-mile-wide waterway near Iran. Tehran has said it will shut down the oil choke point if threatened.

A series of recent incidents have brought Iran back into the market's focus. Analysts and traders said crude prices have been bid up to account for the risk that Iran might try to cut off crude flows. They added that over the last few weeks, this risk has obscured more traditional fundamentals like anticipated global growth or the amount of barrels of crude available on the market.

'Oil isn't trading on fundamentals the way some other commodities are because of the fact you have massive geopolitical concerns about the disruption of supply,' said Ruchir Kadakia, director of global oil fundamentals for IHS Cambridge Energy Research Associates.

Oil prices jumped nearly 5% on July 3 following reports of Iranian military tests and of a U.S. military buildup in the Persian Gulf. Prices rose 3.1% last Thursday after Israel accused Iran of being behind an attack that killed seven Israeli tourists in Bulgaria.

Over the past three weeks, smaller price rises have followed reports of additional U.S. warships being sent to the Gulf; the U.S. imposing additional sanctions -- and even an Indian fisherman being killed after being fired on by a U.S. Navy ship when his boat got too close.

For the markets, 'the overriding concern is that there will be a war in Iran that will disrupt the Strait of Hormuz,' said Phil Flynn, senior market analyst at the Price Futures Group in Chicago, a brokerage firm.

The new tensions renewed an Iranian risk premium, which had eased this spring over optimism that negotiations with Iran might resolve the situation.

Also, anxieties about Iran were trumped by fears that about Greece's debt and the possible collapse of the euro zone. Such a collapse would lead to economic turmoil and undercut demand.

Futures fell 29% from this 2012 high on Feb. 24 to $77.69 a barrel on June 28, the low for 2012.

U.S. crude prices snapped a streak of seven consecutive sessions of gains last Friday, closing down 1.32% to $91.44.
过去三个星期，由于市场对伊朗方面的担忧进一步升级，美国原油期货价格飙升了18%。

原油期货价格的上涨幅度超过了大多数其他资产的价格涨幅。与原油期货一样，股票和铜的价格都与经济增长预期密切相关，但是这两种资产的价格上涨幅度要小得多。过去三周里，标准普尔500指数上涨了2.5%，纽约商品交易所铜期货价格上涨了3%。

Kamran Jebreili/Associated Press与石油不同的是，股票和铜都不需要依赖波斯湾的霍尔木兹海峡进行运输。全世界约20%的石油运输需要途经伊朗附近这条宽24英里的航道。德黑兰方面曾表示，如果受到威胁，它将关闭这条石油运输要道。

最近发生的一系列事件让伊朗重新成为了市场关注的焦点。分析人士和交易员说，由于担心伊朗可能会切断原油供应，原油价格已经被抬高。他们还说，在过去的几个星期，这个风险在影响力方面已经超过了一些更传统的基本面因素，如全球增长预期和市场上的原油供应量等。。

IHS剑桥能源研究公司(IHS Cambridge Energy Research Associates)全球石油基本面研究部负责人卡达基亚(Ruchir Kadakia)说，石油交易受基本面因素的影响程度没有其他一些大宗商品那样大，因为人们需要考虑太多可能导致供应中断的地缘政治的因素。

7月3日，石油价格上涨了将近5%，此前，媒体上曾陆续出现伊朗举行军事演习和美国军方在波斯湾增派兵力的报道。上周四，以色列指责伊朗策划了发生在保加利亚的袭击事件之后，石油价格上涨了3.1%。七名以色列游客在袭击中丧生。

过去三个星期里，美国向波斯湾派遣战舰、美国对伊朗进一步施加制裁，甚至一名印度渔民因太过靠近美国海军船只而被美军射杀的消息都曾导致石油价格小幅上涨。

大宗商品经纪公司Price Futures Group驻芝加哥的高级市场分析师弗林(Phil Flynn)说，对于市场来说，最大的担忧是在伊朗爆发战争，因为这将对霍尔木兹海峡的石油运输线路造成破坏。

新的紧张情绪使油价因伊朗因素而产生的风险溢价再度出现，今年春天，由于人们对能通过与伊朗的谈判来解决问题持乐观态度，这一风险溢价曾一度降低。

此外，当时人们对希腊债务问题和欧元区解体的担忧也缓解了因伊朗问题而产生的焦虑情绪。一旦欧元区解体，将会引发经济动荡，而原油需求也会因此降低。

6月28日，原油期货价格降至每桶77.69美元的2012年以来最低水平，较2月24日的年内峰值降低了29%。

美国原油价格上周五结束了连续七个交易日上涨的趋势，收盘下跌至每桶91.44美元，跌幅1.32%。