Underlying Index Performance: 00639.TW tracks the Taiwan 50 Index. The ETF's price closely reflects the overall performance of these 50 largest Taiwanese companies. Upward or downward movements in the index directly impact the ETF's value.

Supply and Demand: Like any traded security, the interplay of buying and selling pressure affects 00639.TW's price. High demand pushes prices up, while increased selling pressure leads to price declines.

Investor Sentiment: General market optimism or pessimism regarding the Taiwanese economy and stock market can influence investor demand for 00639.TW, impacting its price.

Dividend Payments: Dividends distributed by the underlying companies in the Taiwan 50 Index ultimately affect the ETF's net asset value (NAV) and market price, though often less dramatically than index fluctuations.

Expense Ratio: Although not a direct price driver, the ETF's expense ratio subtly impacts long-term returns. Higher fees can slightly reduce the overall attractiveness and potentially affect trading volume and price.

Currency Exchange Rates: Fluctuations in the exchange rate between the New Taiwan Dollar (TWD) and other currencies can indirectly affect the ETF's price, particularly for foreign investors.

Global Economic Conditions: Broader global economic factors, such as international trade policies, interest rate changes, and global growth prospects, can influence the Taiwanese stock market and, consequently, 00639.TW's price.