历了今年头五个月的大幅飙升后，美元兑欧元和日圆急剧回落，许多交易员认为是美国经济增长放缓及欧洲经济持稳促成了这一跌势。
外汇市场上，交易员们正热烈谈论着还有一个因素在起作用：中国。
交易员们认为最近几个月中国加大了买进日圆及欧元相关投资的力度。有分析师说，这可能是因为中国正试图对其2.5万亿美元的外汇储备进行多元化管理，而不仅仅只是持有美国国债。
有人说，此举将推高中国经济竞争国的货币，从而帮助中国出口商品在全球市场保持具有竞争力的价格，这也许不是一种巧合。
上周五，日圆兑美元飙升至85.03的年内高点，纽约市场上最终收于85.39，上周四尾盘为85.82。欧元触及1.3333美元，为4月份以来的最高水平，最终有所回落，收于1.3293美元，仍高于上周四尾盘的1.3191美元。
考虑到美国超低的利率水平，如果中国要为减少其外汇储备中的美元资产挑选一个明智的时机，那就是眼下。
康 涅狄格州Faros Trading的交易负责人波斯维克(Douglas Borthwick)说，当考虑抛售美元固定收益时，中国必须选择一个适宜的时机。而考虑到利率的相对水平，就收益率而言目前是它抛出美元固定收益产品、 买进日圆和欧元固定收益产品的绝佳时机之一。
和中国的许多事情一样，中国将对其外汇储备和债券持有情况做出何种程度的调整、甚至它是否会做出大幅调整，这些都是未知数。而外汇市场上的许多波动也许都要归因于那些希望从任何此类举动中获利的投资者。
与其他许多央行不同，中国不会公布其外汇储备的构成状况。
结果就是市场参与者玩起了室内游戏，他们在得知其他哪些国家说有谁购买了他们的债券后，再将据此得出的猜测拼凑到一起。由于中国的外汇储备规模庞大，因此即便是细微的变化也会产生大的影响。
许多分析师认为在中国的外汇储备中美国的资产占到了60%至70%。但中国外贸关系的变化意味着仅有20%的中国出口品进入了美国，日本和欧洲已成为中国更大的贸易伙伴。中国还在争夺欧美市场上与日本企业展开了愈加激烈的竞争。
中国一直以来都在购买日本资产。日本方面的数据显示，2010年头四个月间中国增持了62亿美元以日圆计价的国债，这比它2005年所购买日本国债的一倍还多，当时的购买规模创下了纪录。
日 本还说在7月11日至17日这段时间内，由非本国居民大笔购买的日圆货币市场账户的资金总计达107亿美元。美国银行美林(Bank of America Merrill Lynch)指出，这一数据虽未显示由国家划分的情况，但却是自5月份以来水平最高的一周，当时中国正在大举买入日圆债券。
有人认为中国的举动并无异常。
摩 根大通(J.P. Morgan Chase & Co.)全球外汇策略师诺克(Gabriel De Kock)说，由于欧元6月初触及四年低点，中国很自然会最终购买以欧元计价的投资产品，以求调整投资组合。他说，他认为中国的外汇储备投资经理与其他外 储经理没什么不同。
不过，法国投行Natixis驻香港的亚太首席经济学家斯利珀(Luca Silipo)认为，如果未来数月中国继续增持日圆，那么这可能是要服务于一种“长期战略性目标：贸易”。中国与日本高科技企业的竞争日益激烈，而日圆走强使日本商品在价格方面的竞争力不及中国。
斯利珀说，投资者接下来会跟随中国行事，这将进一步推高日圆。美元兑日圆今年已下跌了8%，至86.30日圆，目前正接近去年11月份触及的84.82日圆的低位。美元兑日圆的纪录低点是1990年创下的79.90日圆。
有关中国实现外汇储备多元化的另一个争议在于，中国称人民币将盯住一篮子货币，而非只盯住美元。转向盯住一篮子货币将使中国有理由购入非美元资产，交易员和投资者知道的信息仅此而已。
中国的外汇动向引发了一些报导，说中国最近购买了数亿欧元的西班牙和希腊债券。
After a big surge through the first five months of the year, the dollar has slumped against the euro and yen, with many traders pointing to softer U.S. economic growth and stabilization in Europe as the catalyst.
In currency markets, the buzz among traders is that there is another factor at work, too: China.
In recent months, traders believe, China has stepped up its buying of yen- and euro-based investments. This is likely because it is trying to diversify its $2.5 trillion of currency reserves away from holdings of U.S. Treasurys, some analysts say.
Perhaps not coincidently, some say, such a move would have the effect of pushing up the currencies of economic competitors, helping to keep Chinese exports priced competitively in the world markets.
On Friday, the yen soared to the strongest point of the year against the dollar at 85.03, before finishing at 85.39 yen in New York, compared with 85.82 yen late Thursday. The euro touched $1.3333, the highest since April, before retreating somewhat to end at $1.3293, still up from $1.3191 late Thursday.
Given ultralow U.S. interest rates, if there was a smart time for China to rebalance its currency reserves away from dollar-based investments, it is now.
'When looking at selling out of U.S. fixed income, China has to pick the right time to do so,' says Douglas Borthwick, head of trading at Faros Trading, in Stamford, Conn. Based on the relative levels of interest rates, 'it is one of the best times on a yield basis to sell U.S. fixed income and buy Japanese and European fixed income.'
As with many things China, it is unclear how much, or even whether, it is making meaningful changes to its currency and bond holdings. And many of the currency moves may be attributable to investors hoping to get a jump on any such action.
Unlike many other central banks, China doesn't divulge the composition of its currency reserve holdings.
The result is a parlor game among market participants of piecing together estimates based on what other countries report about who is buying their debt. Given the size of China's currency reserves, even a slight move could have a big impact.
Many analysts peg China's U.S. holdings at 60% to 70% of its reserves. But changes in China's trading relationships mean just 20% of its exports go to the U.S. Japan and Europe have become much bigger trading partners. China also is increasingly competing with Japanese companies for sales in the U.S. and Europe.
China has been buying Japanese assets. Data from Japan show that China increased its holdings of yen-denominated government bonds by $6.2 billion in the first four months of 2010, more than double its previous record purchases of Japanese government bonds in 2005.
Japan also has reported that large purchases of yen money-market accounts by nonresidents totaled $10.7 billion from July 11-17. The data aren't broken down by country, but it is the highest weekly reading since May, when China was snapping up yen bonds, noted Bank of America Merrill Lynch.
Some think China isn't doing anything out of the ordinary.
With the euro having touched a four-year low in early June, China naturally would end up buying euro-denominated investments in order to rebalance its portfolio, says Gabriel De Kock, global foreign-exchange strategist at J.P. Morgan Chase & Co. 'I don't think China's reserve managers are any different from other reserve managers,' he says.
Still, Luca Silipo, Asia-Pacific chief economist for French investment bank Natixis in Hong Kong, thinks China's move to accumulate yen, if the trend continues in the coming months, might serve a 'long term strategic objective: trade.' China increasingly competes with Japan's high technology companies, and a stronger yen makes Japan's goods less competitively priced with China's.
Investors would then follow China's lead, Mr. Silipo says, helping to further propel the yen rally. The dollar has weakened 8% this year to 86.30 yen and now is flirting with last November's low of 84.82 yen. The record low for the dollar was hit in 1990 at 79.90 yen.
Another argument for diversification is that China says it now pegs the yuan to a basket of currencies, rather than the U.S. dollar. While traders and investors have little more information than that, the switch to a basket could be giving China reason to load up on non-dollar assets.
China's currency move has given rise to reports that the country recently bought several hundred million euros of Spanish and Greek debt.