Underlying Index Performance: The price of 00638R.TW closely tracks the performance of its underlying index, which typically consists of a basket of stocks. If the index rises, the ETF's price generally increases, and vice versa.

Supply and Demand: Market forces of supply and demand significantly impact the ETF's price. Higher demand relative to supply pushes the price up, while greater supply compared to demand causes the price to fall.

Net Asset Value (NAV): The NAV represents the per-share value of the ETF's underlying assets. The ETF's market price should ideally align with its NAV, but deviations can occur due to market dynamics.

Market Sentiment: Overall investor sentiment towards the market and specific sectors or asset classes included in the ETF can influence its price. Positive sentiment tends to drive prices higher, while negative sentiment can lead to price declines.

Trading Volume and Liquidity: Higher trading volume and liquidity generally result in tighter bid-ask spreads and more efficient price discovery. Lower liquidity can lead to wider spreads and potentially greater price volatility.

Expense Ratio: While not a direct driver of daily price fluctuations, the ETF's expense ratio, which is the annual fee charged to manage the fund, can indirectly affect returns and investor demand, potentially impacting its price over time.

Economic Conditions: Macroeconomic factors such as interest rates, inflation, and economic growth can influence the performance of the underlying companies in the index and, consequently, the ETF's price.

Currency Fluctuations: If the ETF invests in assets denominated in foreign currencies, fluctuations in exchange rates can affect its price when translated back into the local currency.

News and Events: Company-specific news related to the holdings within the underlying index, as well as broader market or economic news events, can trigger price movements in the ETF.

Investor Perception of Risk: Changes in investors' risk appetite can influence demand for ETFs. During periods of heightened risk aversion, investors may sell off ETFs, leading to price declines. Conversely, increased risk appetite can drive demand and prices higher.