Underlying Asset Performance: The primary driver is the performance of the assets the ETF tracks. If the underlying index or basket of stocks increases in value, the ETF price typically rises, and vice versa.

Supply and Demand: Market forces of supply and demand influence the ETF's price. Higher demand can push the price above its net asset value (NAV), while increased selling pressure can drive it below NAV.

NAV: The net asset value represents the total value of the ETF's holdings minus liabilities, divided by the number of outstanding shares. The market price usually tracks NAV closely.

Expense Ratio: The ETF's expense ratio, which covers management fees and other operational costs, indirectly affects the price by reducing returns. Higher expense ratios can lead to slightly lower relative performance.

Market Sentiment: General market sentiment and investor confidence can impact ETF prices. Positive sentiment often leads to increased investment in ETFs, while negative sentiment can trigger selling pressure.