Stock Market Decline

My Understanding of a One-Day Market Decline (Based on Closing Price). Different opinions are welcome for discussion. 

1. Small Decline: The market (S&P 500 or Nasdaq 100 index) falls by no more than 0.75%.
2. Moderate Decline: The market falls by more than 0.75%, but less than 1.5%.
3. Large Decline: The market falls by more than 1.5%, but less than 2.25%.
4. Plunge: The market falls by more than 2.25%.

Small and moderate declines usually don’t affect the continuation of the trend. However, a large decline or plunge at a high level is often the beginning of a trend reversal.