Regret-aversion bias

An emotional bias that occurs when market participants do nothing out of excessive fear that actions could be wrong. They attach undue weight to errors of commission, that is doing something that turns out wrong, and not enough weight to errors of omission, that is not doing something that would have turned out right. One classic example is individuals who retain most of their wealth in bank savings. They are so afraid that the market will crash that they avoid the stock market, but underplay the strong likelihood that inflation will erode the value of their savings. Their sense of regret and pain is stronger for errors of commission. 

Compare: Status quo bias, Endowment bias