Economy: Economic growth typically boosts stock prices, while recessions can depress them. FSBKX, being a large-cap index fund, is sensitive to overall economic conditions.

Interest Rates: Rising interest rates can make bonds more attractive and potentially decrease the demand for stocks, leading to lower prices for funds like FSBKX.

Inflation: High inflation can erode corporate profits and reduce consumer spending, negatively affecting stock prices and the fund's value. Central bank actions to combat inflation can also impact market sentiment.

Market Sentiment: Investor optimism or pessimism can drive prices up or down, even if underlying fundamentals remain unchanged. FSBKX's price can fluctuate based on prevailing market mood.

Company Performance: The performance of the large-cap companies within the fund's holdings directly impacts its value. Strong earnings and positive outlooks from these companies tend to push the fund price higher.

Geopolitical Events: Global events such as wars, political instability, or trade disputes can introduce volatility and impact stock prices, influencing the value of FSBKX.