上世纪70年代石油危机期间资金流入美国的一幕至今没有再现的迹象，令美国资产的吸引力受到怀疑。
由于石油出口国将利润投资到以美元计价的资产，参与所谓的“石油美元循环”，使美国政府和金融机构都从70年代的油价上涨中得到了好处。
但基金管理公司表示，石油出口国这一次可能认为，美国资产不那么有吸引力了。
“把钱投资到美国使许多人感到非常不安，”对冲基金Clarium资本管理公司（Clarium Capital Management）管理人员彼得·蒂尔（Peter Thiel）表示。
“这可能与上世纪70年代相当不同。”在上世纪70年代，从石油生产商流入美国的资金帮助支持了美元。
分析师表示，在过去3年里，美国的低利率和美元相对欧元汇率的下降，都使以美元计价的投资品种在石油生产国中的受欢迎程度下降。
The influx of money into the US during the 1970s oil shock shows no signs as yet of being repeated, raising questions about the attractiveness of US assets.
Both the US government and financial institutions benefited from rising oil prices in the 1970s as oil-exporting countries invested their profits in dollar-denominated assets, engaging in so-called "petrodollar recycling".
But money managers say oil-exporting countries may not find US assets so appealing this time around.
"There's a lot of nervousness about putting money into the US," said Peter Thiel, managing member at hedge fund Clarium Capital Management.
"It's likely to be quite different to the 1970s."
Recent purchases of US assets by oil-producing countries are hard to track due to a lack of timely data, although fund managers say it is likely at least some oil money is going into US bonds.
Large inflows of money into US Treasury bonds from Asian central banks, buying dollars to curtail rises in their currencies, have been an important factor behind historically low US Treasury yields.
If petrodollars are also invested in the US, it could help keep a lid on yields at a time of record government deficits.
"The natural thing to do as [oil exporters] accumulate reserves is to buy short-term Treasuries," said Mohamed El-Erian, head of the emerging market portfolio at bond fund manager Pimco.
However, any buying has not been heavy enough to have a noticable effect on US markets.
"Any recycling from private oil producers has been limited," said Stephen Roach, chief economist at Morgan Stanley.
Inflows from oil producers helped support the US dollar in the 1970s.
Analysts say low US interest rates and a fall in the US dollar relative to the euro over the past three years have made dollar-denominated investments less popular among oil producing nations.
"The secular bear market in the dollar has encouraged Gulf nations and Russia to diversify away to the euro," said Ashraf Laidi, chief currency analyst at MG Financial Group.
Russia, whose foreign reserves are at record levels of about $90bn, has indicated that it will change its mix away from dollars into euros.
Dwfor Evans, emerging markets strategist at Banc of America Securities, estimates the percentage of reserves held by Russia in US dollars will drop from 70 per cent to about 50 per cent over the next few years. Analysts say oil producing nations are also more inclined than they were in the 1970s to spend money on domestic infastructure or other local investment. Saudi Arabia's benchmark stock index is up 44 per cent so far this year, and the Kuwait Exchange is up 22 per cent.
Meanwhile, anti-terrorism measures aimed at freezing the assets of suspected terrorist groups could dissuade some oil producing countries from investing heavily in the US.