The Risk Assessment Of Jpy And Krw Exchange Rate Before Around The Change Of RMB Exchange Rate

In the first part we study the knowledge of exchange rate, and in second part we study some models of time series analysis, include ARMA, GARCH. In third part we get the exchange ratios of US dollar/Japanese yen, US dollar/Korea won. Then we divide them into two parts at the date July 21, 2005. Then we get the statistical properties of the two kinds of exchange ratios before and after the RMB is overvalued. Using the time series analysis, we get the models of the return rates of the ratios. By doing this we can know the change law of the risk of the exchange ratio after the RMB is overvalued, which is the return ratio risk evaluation. The result of the time series models show that the overvalue of RMB has little influence on the exchange of JPYand KRW.In this paper we study the base knowledge of time series analysis and how to use it in practice, and use it to analysis the return risk of series of USA/JPY and USA/KRW and make model of it, then study the change of their risk return.From July 7, 2005, China is taking a manageable, floating currency policy, which is based on the demands of the market, and changes with a basket of currencies. Instead of being determined by the US dollars only, the RMB exchange ratio will be more elastic. The change of the ratio from soldiery to floating, will surely accompany with the change of the RMB exchange ratio, which will certainly influence not only our own economy but also those countries around us .Especially those who have great relationships with our country in economy like Japan and Korea. the overvalued RMB, the evolution of the RMB exchange ratio policy, has more or less effect on the exchange ratio of those two currency to US dollar asks us to take the floatation and the trends of the ratio into account to evaluate the risks of the ratio.