Please note my statement (re trading, not stock market), the additional explanation from Johnpax, and please stick to the topic.
I am talking about trading, e.g. day-trading, short-term trading, NOT doing a Warren Buffett here.
Statement #1: trading, in a flat overall market, assuming index will rise around the inflation rate, is a zero sum game.
It is not a zero sum game for an individual, who is likely either to win or lose (do either better or worse than the index). But for the sum of all involved participants, it is.
Some will make money, some will lose it. Guys who have insider knowledge, or better software, or who are outright scumbags, or those who can manipulate the market, or those who are married to director's niece are more likely to win. Guys who read and believed some idiotic "Start trading with CFD now" ads will generally provide them with the cash.
Statement #2 - the above is generally, not as well understood as it should be.
Statement #3 - it is in the vested interest of many market participant to attract as many novices as possible into the market
