How is it that before that player won so much I lost way more than I should based on the percentage of the bankroll that I had yesterday? It’s like if other investors divested just before that gambler started winning, leaving me “exposed” to the player. And then, after they have stopped winning, they invest.
These were not 'other investors' but the player who won big himself. He is probably divesting - playing with big stakes - and reinvesting profits.
The only thing I don't understand is how someone can have so much luck for several days in a row.
Oh that is an awesome idea when you think about it! I mean remove all your money from the investment, start gambling, win as much as you can, drop people's money down and make it lower while earning yourself more, then invest all of it to your investment side and suddenly you are 10x more in the bankroll as well. That is really a smart decision if they did that.
However even if that is not the case, when you see someone earning so much from gambling and the investors lose, you do think about investing a lot more right now, that way you would know that the down didn't hurt you much but with more investment the up will help you out. That is really awesome strategy even if you are not the gambler. I personally would do that if I had the chance but I do not have that much money.
This calculation may work on the paper but practically this is not possible. Consider for a moment that you jump in gambling and lose all of your money or 50% of your money. Then you will have less money left for investment. I don't think it is a wise idea to play gambling only to increase your bankroll. You can lose all of your bankroll in gambling.