Interest Rates: Rising interest rates typically cause bond prices, including those in TGBLX.US, to fall, as newly issued bonds offer higher yields, making older bonds less attractive.

Inflation: Higher inflation erodes the purchasing power of fixed income payments, prompting investors to demand higher yields, which decreases bond prices within the fund.

Credit Risk: Downgrades or perceived increases in the credit risk of the bonds held within TGBLX.US can lead to lower prices as investors demand a higher return to compensate for increased risk.

Economic Growth: Strong economic growth often leads to higher interest rates and inflation, which can negatively affect bond prices in TGBLX.US. Slower growth may have the opposite effect.

Market Sentiment: General investor confidence or fear can influence demand for bonds. Increased risk aversion may drive investors toward safer assets like government bonds, potentially increasing prices, while optimism could lower demand and decrease prices.