Underlying Asset Performance: The price of 00900.TW is directly influenced by the performance of the stocks it holds. If the underlying stocks increase in value, the ETF's price will likely rise. Conversely, if the stocks decline, the ETF's price will likely fall.

Supply and Demand: Market forces of supply and demand also play a role. Higher demand for the ETF, compared to its supply, can drive the price upwards. Increased selling pressure can decrease the price.

Expense Ratio: Although not directly impacting daily price fluctuations, a higher expense ratio can gradually erode the ETF's returns, indirectly affecting its long-term price performance compared to similar ETFs.

Management Efficiency: The fund manager's ability to effectively track the underlying index or strategy influences the ETF's performance and, consequently, its price. Better tracking leads to better price alignment.

Market Sentiment: Overall market sentiment (bullish or bearish) towards the Taiwanese stock market and the specific sectors represented in the ETF can affect investor demand and the ETF's price.