This difference is expressed by the term volatility . But one dollar invested in stocks can rise or fall dramatically. Therefore, stocks are considered to be much riskier than T-bills. However, volatility is not a reason to avoid stocks any more than it is a reason to own them. Rather, volatility is merely a characteristic of stocks.
Prices go up, and prices go down.
And they do that a lot. That's extreme volatility. Yet all these gyrations have occurred on an upward slope. So, you need to focus not on the daily activity of the market, but on its long-term trend. At that rate, stocks would be completely wiped out in just eight months.