Large-cap stock is generally considered less volatile than stock in smaller companies, in part because the bigger companies may have larger reserves to carry them through economicdownturns. They are also called Blue Chip Stocks.
However, market capitalization is always in flux. Today's large-cap stock can drop out of that category if the share price plunges either in a general market downturn or as a result of internal problems.
And the opposite is true as well. Many of the country's largest companies began life as start-ups.