I did something similar to this in high school a few years ago. I ended up losing to another team in the class that bought Gamestop and other related stocks. I stuck with stocks like Intel and GE. If the game had ended even a two weeks later, I would have won.

These games teach high school students very little about investing, especially long term. The other team's strategy was simply "I play video games and I like Gamestop, so let's buy Gamestop!".

For non-professional investors, the "so let's buy Gamestop" strategy isn't necessarily a bad strategy. Assuming you are putting the bulk of your investments in low cost index and mutual funds, using a little bit of you savings to play the market by investing in companies that you are familiar with can be productive. I've had some big hits and some big misses, but overall, my picks have matched the pace of my index/mutual funds.

Our school once had this competition as well. Given the short time period of these competitions, you have to buy high beta stocks in order to do well, or very low beta if the market is falling overall.

In order to win this a friend and I decided to team up and split the winnings. Basically what we did was to get one of us to buy the riskiest investments that we could (penny stocks, other low cap stocks, risky derivatives etc.) and the other would short them. This way over the course of the few weeks one of us would be dead last, and the other far ahead.

Worked like a charm.