Foreign investment (FI) has been identified with a recent spate of speculat
ive attacks on certain foreign currencies, giving rise to several financial
crises. The issue of whether or not FI has destabilization or demonstratio
n effects on the stock and foreign exchange markets has therefore received
widespread attention in developing countries. The destabilization effect fo
cuses on whether FI increases or decreases the volatility of stock prices a
nd foreign exchange markets. The demonstration effect stresses that because
FI focuses more on fundamental factors than nonfundamental factors, the ma
jor influencing factors on stock markets may change after FIs are permitted
to enter into a country. The experience of Taiwan in this regard can funct
ion as a guide for other developing countries. This paper finds, regarding
the destabilization effect, that FI has a positive influence on the volatil
ity of the exchange rate and a mild influence on the volatility of stock re
turns. These results imply that challenges will probably emerge during the
process of liberalization, such as increased volatility in stock returns an
d in the exchange rate. Next, with regard to the demonstration effect, our
results show that prior to the inflow of FI, stock returns are mainly affec
ted by nonfundamental factors, such as the turnover rate. After the inflow
of FI, stock returns are affected by both nonfundamental and fundamental el
ements.