13 year old - too cocky

My son is 13, and is currently involved with the ASX Stock market game through school.

He has invested in TPM, FLT, BRG and IIN.

So far, he is doing very well - ranking at approx. 200th in Australia out of approx. 17,000 students participating.

Now it really is more ass than class that he's picked these well performing stocks - pure fluke IMO.

I asked him what research he did, and he said

"None - just looked at the chart, it was going up, so I bought them".

He is in front of all of his peers at school by miles, and is as cocky as because he's "backed some winners" so to speak.

The point in this post.

I just wanted others opinions on whether this is a dangerous game for young impressionable 13 year olds to be playing.

Is this suitable for Year 9 students?

Thoughts?