Is the corporate bond of AA- safe?

The bond rating results are relative. Judging from the setting of credit rating sequence, AA bonds are very safe, and the negative sign indicates that the repayment guarantee of these bonds is weak in AA category, but they are still very safe as a whole. At present, there is no default on domestic bonds, but even if the rating is AA-, it does not mean that there will be no default in the future. First, the credit rating may track upward or downward changes; Moreover, the standards of each rating company are different.