I have my money( no great pile but too much to lose) invested in very conservative stocks through banks and credit unions investment funds, even then I took a hit of a few thousand dollars, but I didn't panic and sell, so I hope it will come back and gain and pay me dividends to supplement my pensions. Like you say these billionaires can cause panic amongst small investors just by selling a few million shares which will bring down the value of the shares, small investors panic and sell off even more furthering the slide in value, when it reaches a certain level, billionaires will buy up those low priced shares, driving up the value again. There should be laws to prevent this from happening but no one wants to touch these rich people, especially governments.