This is because of the point above about these stocks being more risky than larger company stocks. (modestmoney.com)
In addition to stocks of large companies, the Funds invest in small - and mid-sized companies that are generally less liquid and more volatile than large companies. (heartlandadvisors.com)
Small companies are more volatile and riskier than larger companies because they have less business diversification, fewer financial resources and greater uncertainty of earnings than their large counterparts. (ifa.com)