Which of the following factors does NOT affect bond yields?

Bond yields are influenced by various factors that relate to the broader economic environment and investor behavior. While market supply and demand, central bank policies, and geopolitical issues certainly play critical roles in shaping bond yields, corporate earnings reports primarily impact equity markets rather than fixed income securities like bonds.

Market supply and demand directly affect bond yields because when there are more buyers than sellers, bond prices increase and yields decrease, and vice versa. Central bank policies, such as interest rate changes or quantitative easing, also have a significant impact on bond yields, as these decisions influence the cost of borrowing and overall economic conditions. Geopolitical issues can create uncertainty in financial markets, affecting investors' risk appetite and thus influencing bond yields.

In contrast, corporate earnings reports are focused on individual companies and their financial performance, which tends to influence stock prices more than bond yields. Therefore, while all the other factors are interrelated within the financial markets, corporate earnings reports do not have a direct effect on bond yields.