Underlying Index Performance: FTSM.US mirrors the FTSE All-World ex US Index. Its price is heavily influenced by the performance of the constituent stocks within that index.

Supply and Demand: Like all ETFs, FTSM.US's price is determined by the forces of supply and demand in the market. Higher demand pushes the price up, while increased selling pressure causes it to fall.

Currency Fluctuations: Since the ETF holds international stocks, currency exchange rates between the US dollar and the currencies of the underlying assets impact the ETF's value. A strengthening dollar reduces returns.

Expense Ratio: The annual fee charged by the ETF provider (expense ratio) indirectly affects returns, as it reduces the overall profitability and potentially the ETF's appeal.

Tracking Error: The degree to which the ETF accurately replicates the performance of its benchmark index (tracking error) can affect its price relative to what might be expected based solely on the index's performance.