One scam that has become more sophisticated recently is the "pump and dump" scenario. In this scam, you will get a phone call, e-mail, letter, or fax offering you a tip about a hot stock. The tip is false! Many companies fall on hard times but fill out a public registration statement so that they can issue the stock to the people. They are worthless -- a "shell" company. Criminals will buy stock in such companies and put out false press releases, phone calls and e-mails about the investment opportunity. People will then buy this stock, and the price will rise. Then, the criminals sell their share for many more times what they paid. However, there was one "pump and dump" scam that was so over the top that the criminals got caught. In Florida, the criminals called and left voicemails around the country, pretending that the call was for someone else about an insider tip. So when you get information touting a hot stock, be on guard! You might just get scammed! Instead, Clark says you always have to do your homework and research a company thoroughly before investing.