The key is not letting your losses affect your bet amount. With the gain being only 80% instead of 100%, betting your bank means 1 win and 1 loss leaves you with less than you started. Making your bet amount fixed between flips means 1:1 will instead give you a net gain. The Kelly Criterion says there is an optimal proportion of bank you can bet that will maximize this gain over many flips
limitedduck
joined 1 year ago
This is true if you're betting everything you have. By not having shrinking bets after losses you can tap into the net gains. Compare 1 win followed by 1 loss with $100 start:
Win is $100+$80 = $180
Loss is $180-$90 = $90
Compare with fixed bets of $50 with bank of $100:
Win is $100+$40 = $140
Loss is $140-$25 = $115