Am I right to be worried about my retired parents' investment strategy?

For the past 5 years my dad has been investing according to the teachings of Investors Business Daily and MarketSmith. I don't know much about these, but it appears to be entirely technical in nature, looking at trends on graphs and numerical metrics and such. He's seen really good (40%+ YTD) gains on his stocks, and even 300 - 400% on some individual stocks, but here is his portfolio: 0% bonds. 30% aggressive tech mutual funds 70% in ten tech stocks (mostly enterprise software) My parents are both retired and my dad is doing all the investing. When I ask him about any individual stock he has no idea what they do or any of their business plans or their competition or details of the industry they're in. He simply says that they're rated very highly in MarketSmith and he buys based on the metrics it gives him. He never talks in terms of "why" a certain stock is doing this or that but only in terms of how much it has grown. Anyone have any experience with MarketSmith and such? I... Read more