However, when checking the same merchant's price on eBay or the merchant's Web site is only a click away, the ability for Amazon to increase margins is naturally constrained. Why should Amazon investors anticipate higher share prices if product sales margins and merchant fees remain under pressure? My good friend Rocco Pendola correctly pointed out in Apple Competes With Its Unwritten Future that investors of almost all timeframes have made money. One very popular investing style that never appears to go out of fashion is the musical chair method. I refer to it as the Thanksgiving turkey theory of investing. If you read "Fooled by Randomness" and "The Black Swan" by Nassim Nicholas Taleb, you know how this investment thesis concludes. Taleb brilliantly illustrates the potential error in assuming the future by using the past. Imagine a turkey on a farm and its relationship with the farmer. Each day the farmer comes to the turkey and brings the turkey food. Each day the turkey grows to trust the farmer more than the last. There is no reason not to trust the farmer. After all, the farmer provides shelter, water and food. It doesn't take long for the turkey to view the farmer as its support and that the farmer will be there for him every day with more food and water. This is the same as many investors and analysts view Amazon. They see the chart moving higher and higher and see no reason for it to stop. This, that and the other thing will happen, and everything is pointing towards a higher stock price. In fact, if you had suggested a year ago that it was time to sell Amazon, look how foolish you would appear right now. The turkey feels the same way, and on the day before Thanksgiving the turkey trusts the farmer more than any other point. It's the day the turkey holds the highest amount of trust that the farmer approaches with an axe instead of a daily ration of food. The incredibly fantastic share price leads me to believe that Amazon is either in or near its own November, otherwise I wouldn't sound the warning bells to be careful. If you buy Amazon, you may want to keep an eye out for Walmart, Target and other retail giants to see if they turn into a farmer. At the time of publication the author had no position in any of the stocks mentioned.Follow @RobertWeinsteinThis article was written by an independent contributor, separate from TheStreet's regular news coverage.