FNY.US, or the First Trust Mid Cap Growth AlphaDEX Fund, is an ETF whose price is influenced by several factors. Holdings Performance: The underlying stocks held within the FNY ETF directly impact its price. Positive performance of these mid-cap growth companies generally pushes the ETF price higher.

Market Sentiment: Overall market trends and investor sentiment towards growth stocks affect demand for FNY, influencing its price. Positive market sentiment can drive up prices, while negative sentiment can lead to price declines.

Sector Performance: The sectors in which the ETF's holdings operate contribute to its overall performance. If the sectors are performing well, it helps the ETF, and vice versa.

Expense Ratio & Fees: The fees associated with managing the fund can indirectly affect its price compared to other similar ETFs. Higher expense ratios can make it less attractive to investors.

Supply and Demand: Basic economic principles of supply and demand apply. Higher demand for FNY relative to its supply drives up the price, while increased supply relative to demand pushes it down.

Index Tracking: FNY aims to track an underlying index. How closely it follows that index's performance affects its perceived value and market price.