Stock prices can be affected by numerous factors and criminals, using less than ethical means can get stock prices or a particular company to go up or plummet. They'll make some quick profits, head off elsewhere and do the same thing. According to the writer of the article linked to below, the Securities and Exchanges Commissions can do nothing to stop such criminals. http://www.businessinsider.com/crim...et-and-regulators-cant-seem-to-stop-it-2015-8 On May 14 a Bulgarian stock schemer is alleged to have moved the share price of consumer company Avon Products by making a false filing to the Securities and Exchange Commission. Three months later, nothing is stopping someone else from doing the very same thing. The Avon M&A escapade is far from the only example of crooks using false filings in an to attempt to dupe a bigger cross-section of market players. Stock market fraudsters have also tried to dupe reputable public relations companies with false reports in hopes of catching investors off-guard.