Foreign exchange reserves

本文介绍了外汇储备的概念,包括其历史背景、目的、成本与收益等内容。外汇储备是中央银行持有的外币存款,用于支撑本国货币稳定及金融系统的安全性。文章还列举了2007年持有大量外汇储备的主要国家和地区。
Foreign exchange reserves are the foreign currency deposits held by central banks and monetary authorities. These are assets of the central banks which are held in different reserve currencies such as the dollar, euro and yen, and which are used to back its liabilities, e.g. the local currency issued, and the various bank reserves deposited with the central bank, by the government or financial institutions.
Contents
[hide]

* 1 History
* 2 Purpose
* 3 Costs and benefits
* 4 Levels
* 5 See also
* 6 External links
o 6.1 Articles
o 6.2 Data
o 6.3 Speeches

History

Reserves were formerly held only in gold, as official gold reserves. But under the Bretton Woods system, the United States pegged the dollar to gold, and allowed convertibility of dollars to gold. This effectively made dollars appear as good as gold. The U.S. later abandoned the gold standard, but the dollar has remained stable as a fiat currency, and it is still the most significant reserve currency. Central banks now typically hold large amounts of multiple currencies in reserve.

Purpose

In a non fixed exchange rate system, reserves allow a central bank to purchase the issued currency, exchanging its assets to reduce its liability. The purpose of reserves is to allow central banks an additional means to stabilise the issued currency from excessive volatility, and protect the monetary system from shock, such as from currency traders engaged in flipping. Large reserves are often seen as a strength, as it indicates the backing a currency has. Low or falling reserves may be indicative of an imminent bank run on the currency or default, such as in a currency crisis.

Central banks sometimes claim that holding large reserves is a security measure. This is true to the extent that a central bank can prop up its own currency by spending reserves. (This practice is essentially large-scale manipulation of the global currency market. Central banks have sometimes attempted this in the years since the 1971 collapse of Bretton Woods. A few times, multiple central banks have cooperated to attempt to manipulate exchange rates. It is unclear just how effective the practice is.) But often, very large reserves are not a hedge against inflation but rather a direct consequence of the opposite policy: the bank has purchased large amounts of foreign currency in order to keep its own currency relatively cheap.

Costs and benefits

On one hand, if a country desires to have a government-influenced exchange rate, then holding bigger reserves gives the country a bigger ability to manipulate the currency market. On the other hand, holding reserves does induce opportunity cost. The "quasi-fiscal costs" of holding reserves are the gap between the low-yield assets that returns managers typically hold, and the average cost of government debt in the country. In addition, many governments have suffered huge losses on the management of the reserves portfolio - all of which is ultimately fiscal. When there is a currency crisis and all reserves vanish, this is ultimately a fiscal cost. Even when there is no currency crisis, there can be a fiscal cost, as is taking place in 2005 and 2006 with China, which holds huge USD assets but the CNY has been continually appreciating.

Levels
Foreign exchange reserves by country
Foreign exchange reserves by country

At the end of 2004, 66% of the identified official foreign exchange reserves in the world were held in United States dollars and 25% in euros [1].
Monetary Authorities with the largest foreign reserves in 2007. Central Bank/Monetary Authority billion USD (end of month)
Flag of People's Republic of China People's Republic of China $1066 (December)1
Flag of Japan Japan $905 (February)
Flag of Russia Russia $317 (March 09)2
Flag of Republic of China Republic of China (Taiwan) $268 (February)
Flag of South Korea South Korea (South Korea) $243 (February)
Flag of India India $194 (March 09)3
Flag of Singapore Singapore $139 (February)
Flag of Hong Kong Hong Kong, China $136 (February)
Flag of Germany Germany $113 (January)
Flag of Brazil Brazil $107 (March 20)4

Note:

* Note 1: China updates its information quarterly.
* Note 2: Russia updates its information weekly and monthly.
* Note 3: India updates its information weekly.
* Note 4: Brazil updates its information daily.

These few holders account for more than 50% of total world foreign currency reserves.

The adequacy of the foreign exchange reserves is more often expressed not as an absolute level, but as a percentage of short-term foreign debt, money supply, or average monthly imports.

See also

* International reserve system
* Balance of payments
* Official gold reserves
* Reserve currency
* Special Drawing Rights

External links

Articles

* Guidelines for foreign exchange reserve management
* A primer on exchange reserves
* An empirical analysis of foreign exchange reserves in emerging Asia -- December 2005
* Foreign exchange reserves: issues in asia -- January 2005
* Foreign exchange reserves in east asia: why the high demand? -- April 25, 2003
* Optimal currency shares in international reserves
* The adequacy of foreign exchange reserves

Data

* IMF's data on current foreign exchange reserves of reporting countries
* Taiwan's Department of Investment Services data on foreign exchange reserves of major countries
* Bank of Korea's top ten foreign exchange reserves holding countries monthly

Speeches

* Alan Greenspan: discusses recent trends in the management of foreign exchange reserves -- April 29, 1999
* Y V Reddy: India’s foreign exchange reserves - policy, status and issues -- May 10, 2002
* Marion Williams: foreign exchange reserves - how much is enough? -- November 02, 2005
Java是一种具备卓越性能与广泛平台适应性的高级程序设计语言,最初由Sun Microsystems(现属Oracle公司)的James Gosling及其团队于1995年正式发布。该语言在设计上追求简洁性、稳定性、可移植性以及并发处理能力,同时具备动态执行特性。其核心特征与显著优点可归纳如下: **平台无关性**:遵循“一次编写,随处运行”的理念,Java编写的程序能够在多种操作系统与硬件环境中执行,无需针对不同平台进行修改。这一特性主要依赖于Java虚拟机(JVM)的实现,JVM作为程序与底层系统之间的中间层,负责解释并执行编译后的字节码。 **面向对象范式**:Java全面贯彻面向对象的设计原则,提供对封装、继承、多态等机制的完整支持。这种设计方式有助于构建结构清晰、模块独立的代码,提升软件的可维护性与扩展性。 **并发编程支持**:语言层面集成了多线程处理能力,允许开发者构建能够同时执行多项任务的应用程序。这一特性尤其适用于需要高并发处理的场景,例如服务器端软件、网络服务及大规模分布式系统。 **自动内存管理**:通过内置的垃圾回收机制,Java运行时环境能够自动识别并释放不再使用的对象所占用的内存空间。这不仅降低了开发者在内存管理方面的工作负担,也有效减少了因手动管理内存可能引发的内存泄漏问题。 资源来源于网络分享,仅用于学习交流使用,请勿用于商业,如有侵权请联系我删除!
### 相关原因 - **内存统计不准确**:系统在统计空闲高原子储备时可能存在算法缺陷,导致对实际可用内存的高估。高原子储备通常用于内核的一些关键操作,如DMA(直接内存访问)。如果统计不准确,系统会认为有足够的内存可供使用,从而分配过多的内存给进程,最终导致OOM。例如,在一些复杂的内存管理场景下,内存碎片可能没有被正确考虑,使得统计的空闲内存比实际可用的要多。 - **内核配置问题**:内核的一些参数配置可能会影响高原子储备的统计和使用。比如,`vm.min_free_kbytes` 这个参数设置不合理,可能会导致系统在内存紧张时无法正确保留足够的高原子储备,进而高估了空闲的高原子储备。 - **动态内存分配策略**:现代操作系统采用动态内存分配策略,当有新的进程请求内存时,系统会尝试满足这些请求。如果系统没有对高原子储备进行有效的监控和限制,就可能会在高估的情况下过度分配内存给进程,最终引发OOM。 ### 解决方案 - **优化内存统计算法**:开发人员可以对内核的内存统计算法进行优化,考虑更多的因素,如内存碎片、缓存等,以提高空闲高原子储备统计的准确性。例如,引入更复杂的内存碎片检测和整理机制,确保统计的空闲内存是真正可用的。 - **调整内核参数**:合理调整与内存管理相关的内核参数,如 `vm.min_free_kbytes`。可以通过修改 `/etc/sysctl.conf` 文件来调整这些参数,然后使用 `sysctl -p` 命令使修改生效。例如,适当提高 `vm.min_free_kbytes` 的值,确保系统在内存紧张时有足够的高原子储备。 ```bash # 修改 /etc/sysctl.conf 文件 echo "vm.min_free_kbytes = 102400" >> /etc/sysctl.conf # 使修改生效 sysctl -p ``` - **实施内存监控和限制**:使用监控工具(如 `top`、`htop`、`vmstat` 等)实时监控系统的内存使用情况,特别是高原子储备的使用情况。同时,可以通过 `cgroups`(Control Groups)对进程的内存使用进行限制,防止某个进程过度消耗内存。例如,创建一个 `cgroup` 并限制某个进程组的内存使用: ```bash # 创建一个 cgroup mkdir /sys/fs/cgroup/memory/mygroup # 设置内存限制 echo "100M" > /sys/fs/cgroup/memory/mygroup/memory.limit_in_bytes # 将进程添加到 cgroup echo $PID > /sys/fs/cgroup/memory/mygroup/cgroup.procs ```
评论
成就一亿技术人!
拼手气红包6.0元
还能输入1000个字符
 
红包 添加红包
表情包 插入表情
 条评论被折叠 查看
添加红包

请填写红包祝福语或标题

红包个数最小为10个

红包金额最低5元

当前余额3.43前往充值 >
需支付:10.00
成就一亿技术人!
领取后你会自动成为博主和红包主的粉丝 规则
hope_wisdom
发出的红包
实付
使用余额支付
点击重新获取
扫码支付
钱包余额 0

抵扣说明:

1.余额是钱包充值的虚拟货币,按照1:1的比例进行支付金额的抵扣。
2.余额无法直接购买下载,可以购买VIP、付费专栏及课程。

余额充值