S&P 500 performance: SPIR's price tends to correlate with the overall performance of the S&P 500 index as it aims to track it.

Economic data: Inflation reports, interest rate decisions, and GDP growth figures can influence investor sentiment and market movements, impacting SPIR.

Market sentiment: Broad investor confidence or fear can drive buying or selling pressure across the market, affecting even index-tracking ETFs like SPIR.

Expense ratio: A higher expense ratio compared to similar ETFs may make SPIR less attractive to some investors, potentially impacting its price slightly.

Trading volume: Higher trading volume typically indicates greater liquidity and investor interest, potentially leading to more stable price movements in SPIR.

Sector performance: Significant underperformance or outperformance of major sectors within the S&P 500 can indirectly affect SPIR's price.

Company performance: Earnings reports and outlooks from large companies within the S&P 500 (held by SPIR) will impact fund price.

Alternatives: The availability of other similar ETFs with lower expense ratios or slightly different tracking strategies can affect demand for SPIR.