What caused the corporate bond spread to widen significantly during the 2008 market crash?

The widening of the corporate bond spread during the 2008 market crash primarily stemmed from heightened concerns regarding the creditworthiness of corporate bond issuers. During times of financial distress, such as the 2008 crisis, investors tend to become increasingly risk-averse, and their confidence in the ability of corporations to meet their debt obligations diminishes. This leads to a sell-off of corporate bonds, as investors seek to unload higher-risk assets for safer alternatives.

When corporate bond issuers are perceived as more likely to default compared to government issuers, the market responds by demanding a higher yield on corporate bonds. This increase in yield reflects the greater risk associated with holding corporate debt versus safer government securities, thus resulting in wider spreads between corporate bonds and government bonds. The perception that corporate entities could face bankruptcy, particularly during an economic downturn, compounded this issue, leading to significant widening of spreads as investors sought to mitigate their exposure to potential defaults.