Underlying Assets: The price of 00668.TW is primarily driven by the prices of the securities it holds. Fluctuations in the prices of these underlying assets, such as stocks, directly impact the ETF's value.

Supply and Demand: Market forces of supply and demand play a significant role. Higher demand for the ETF relative to its supply tends to push the price upward, while increased supply relative to demand can cause the price to decline.

Net Asset Value (NAV): The NAV, representing the total value of the ETF's assets minus liabilities divided by the number of outstanding shares, acts as a theoretical fair value. Deviations between the market price and NAV can present arbitrage opportunities and influence price adjustments.

Market Sentiment: Overall investor sentiment towards the sectors or asset classes represented by the ETF can affect its price. Positive market sentiment may drive increased investment and higher prices, while negative sentiment could lead to selling pressure and price declines.

Index Tracking: 00668.TW aims to track a specific index. Its price is influenced by how closely it replicates the index's performance. Tracking errors, or deviations from the index, can impact the ETF's price relative to the index's movements.

Expense Ratio: The ETF's expense ratio, which covers management fees and operating costs, indirectly affects its price by reducing the overall return to investors. Higher expense ratios can make the ETF less attractive compared to similar ETFs with lower costs.

Currency Exchange Rates: If the underlying assets are denominated in a foreign currency, fluctuations in exchange rates between the local currency and the foreign currency will affect the price.

Interest Rates: Changes in interest rates can influence investor preferences for different asset classes and thus affect the demand for and price of the ETF.