S&P Midcap 400 Performance: PDP tracks the S&P Midcap 400 index, so its price closely mirrors the index's performance. Positive index returns generally lead to a higher PDP price.

Sector Performance: The sectors represented in the S&P Midcap 400 influence PDP. Strong performance from key sectors boosts the ETF, while weakness weighs it down.

Market Sentiment: Overall investor optimism or pessimism affects demand for mid-cap stocks, impacting PDP's price. Broad market rallies benefit PDP.

Economic Data: Economic indicators like GDP growth, inflation, and unemployment influence market sentiment and company earnings, indirectly affecting PDP.

Interest Rates: Interest rate changes can affect borrowing costs for companies in the S&P Midcap 400, impacting their profitability and ultimately PDP's price.

Fund Flows: Significant inflows into PDP typically increase its price, while outflows can put downward pressure on the price.

Expense Ratio: While not a direct price driver, the expense ratio impacts the overall return on investment for PDP over the long term.