在1990年代以後，由於跨境的歐洲通貨交易與債券投資盛行，致利率與債券殖利率在理論上與實務上均係決定匯率之重要因素。至於股市對於匯率決定的影響力，則顯得微不足道。然而，到了1990年代中期之後，尤其是在1999年間，跨國股票投資卻對匯率走勢發揮了舉足輕重的影響力，致傳統的匯率預測模型幾無用處，甚至於大部份外匯交易員改以美國股價走勢測美元匯率。 本文提出匯率與股市密切相關之假說，企圖實證分析1979年至2000年股市與匯率間之關係。本文利用相關分析，並輔以輕濟分析等方法，研究其間之因果關係。研究結果顯示，早期股市與匯率間之關係並不太密切，惟1980年代曾發生短暫性密切關關，而近數年來由於美國新經濟導致股市呈現大多頭行情，其投資收益遠高於歐洲通貨存款與債券，因而全球盛行跨國股票投資，致股市與匯率間之關係因而強化。因此，現在的股票風險溢價已和過去的利率一樣，在匯率決定上扮演非常重要的角色。然而，新經濟通貨膨脹與經濟成長間抵換關係之消失，究竟係肇因於資訊科 技革命所引發的永久性經濟結構改變，戶或僅係受暫時性生產力提高之衝擊，仍有待觀察，致本文綜合分析研判，目前股市與匯率間關係強化之情況是否能持續，仍存在不確定性，因而尚不能據以推論利息平價定理已然失效。亦即利率未來仍可能是決定匯率的重要因性，而傳統的匯率決定理論並未產生結構性的改變。至於股市與利率兩項因素，於對匯率的決定，未來何者將占較突出的地位，須視當時的投資環境而定。

Before the 1990s, Eurocurrency interest rates and bond prices were paramount in determining foreign exchange rates in either theory or practice. Statistical analysis suggested no meaningful relationship between the stock market and foreign exchange rates. However, one of the big changes in foreign exchange in the latter part of the 1990, particularly in 1999, rose importance of stock market to foreign exchange market.. Most foreign exchange traders rely ion the US stock market to forecast exchange-rate trends. This study examines the relationship between stock market and foreign exchange rates from 1979 though 2000. We investigated the causality between them by methods of correlation analysis with economic analyses. The results of the analyses show that the relationship between them has strengthened markedly over the past several years. In conjunction with the tremendous rise in international stock investment throughout the world since the stunning returns that stocks have produced have increased the perceived opportunity cost of remaining in bonds. Therefore, stock risk premiums function in exchange-rate determination now much like those interest rate differentials did before. However, historical evidence showed that the paradigm of exchange-rate determination does not shift, interest rates are still the key determinants of exchange rates too, and the conclusion is that which of them will occupy as prominent a place in exchange-rate determination depends on the global investment climate then.