Capital structure of a firm:

The trade-off theory relies on the threat of financial distress. But why should a public corporation ever have to land in financial distress? According to the theory, the firm should operate at the top of the curve in Figure 18.2. Of course market movements or business setbacks could bump it up to a higher debt ratio and put it on the declining, righthand side of the curve. But in that case, why doesn't the firm just issue equity, retire debt, and move back up to the optimal debt ratio? What are the reasons why companies don't issue stockor enough stockquickly enough to avoid financial distress?