This article from XTB explains the core differences between investors holding shares as opposed to bonds. When you’re a shareholder you are a part owner of the company while if you’re a bondholder the company owes you money.
So, when there’s a time of negative sentiment or a poor profit expected, the share and bonds price react differently. Shares would most likely fall as the perceived value of the worth of the company is less than before. However, for bonds the bondholder is still owed the same amount of debt and as the company still has assets and cash in the bank then the debtholder knows with certainty that they will be repaid. This ensures that bond prices are less volatile and as seen with the attached AMP example, bond prices have consistently outperformed equity (5 times) over the last 18 months.
This is why PE Capital invests a significant component of its Monthly Yield Fund into bonds.