Underlying Holdings' Performance: APRT.US aims to track an index; therefore, the ETF's price heavily relies on the collective performance of the underlying assets, like stocks or bonds, within that index.

Supply and Demand: Market forces play a significant role. Higher demand for APRT.US relative to supply will push the price up, while increased selling pressure can drive the price down.

Expense Ratio: The ETF's management fee (expense ratio) indirectly affects the total return and thus the price over time. Higher fees can slightly detract from performance compared to similar lower-fee ETFs.

Index Rebalancing: When the underlying index is rebalanced (assets added or removed), APRT.US must adjust its holdings accordingly. This activity can temporarily influence the price.

Currency Fluctuations: If the ETF holds assets denominated in a foreign currency, changes in exchange rates can affect the USD value of the ETF, impacting its price.

Interest Rates: Changes in prevailing interest rates, especially if the ETF holds bonds or debt instruments, can affect the ETF's yield and attractiveness, thus impacting its price.