Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

What traditionally happens to bonds when the stock market crashes?
The short answer is if you own a representative index of global bonds (say AGG) and global stocks (say ACWI) the bonds will generally only suffer minimally in even the medium large market crashes you describe.  However, there are some caveats. Not all bonds will tend to react the same way.  Bonds that are considered higher-yield (say BBB rated and below) tend to drop significantly in stock market crashes though not as much as stock markets themselves.  Emerging market bonds can drop even more as weaker foreign currencies can drop in global crashes as well. Also, if a local market crash is caused by rampant inflation as in the US during the 70s-80s, bonds can crash at the same time as markets.  There hasn't been a global crash caused by inflation after countries left the gold standard, but that doesn't mean it can't happen. Still, I don't mean to scare you away from adding bond exposure to a stock portfolio as bonds tend to have low correlations with stocks and significant returns.  Just be aware that these correlations can change over time (sometimes quickly) and depend on which stocks/bonds you invest in.