Optimists hold good positions. When the market falls and the margin is insufficient, the brokerage firm will inform the holder that it is necessary to increase the margin (or make up the position). This market situation can be said that the holder is forced to open a position.
When the market price rises and the margin is insufficient, the brokerage firm will inform the holder that it is necessary to increase the margin (or cover the position). This kind of market can be said that the holder is forced to open a position.
For example, doing futures investment and arranging stock investment with stock financing. Will have the opportunity to be forced.