This can happen when your percentage of the Tote dividend adds up to less than the amount of money you staked on the bet.
For example, in the bet below, we have placed a $10 trifecta bet where our payout will be 4.76% of the trifecta dividend. As the trifecta paid $27.40 in this case, we calculate our payout like this: 0.476 x 27.4 = $1.30