[kasey_junk]

The zero sum counterparty view of each individual trade is as incorrect as the ‘not playing against other people’ view because it doesn’t account for risk/liquidity across time and space.

If I’m using the market to grow wealth for (example) a child’s college fund, it is largely immaterial if my counterparty then later makes more money holding what I sold to them. More power to them, I needed to be liquid and they made that possible. We both got utility out of the trade.

Similarly, I’ve written HFT algo strategies myself that would aggressively take on losers because by doing so I could get to higher rebate levels. Virtually any modern portfolio is going to be taking on expected losers to de risk the whole portfolio, thats money management 101 stuff. In both of those cases ‘professionals’ ‘lost’ to ‘dumb’ money but everyone received utility from it.

[csa]

Yeah. That's precisely why I wrote "in an oversimplified way".

Note that you are taking a relatively sophisticated view of financial instruments, and the original poster was not. There is a difference, and that difference was exactly what I was trying to highlight in a simple way.