Thus, for instance, if 25 people were to put $1,000 each into a tontine – for a total contribution of $25,000 – and the tontine stipulated that it would pay out 6%, each year the $25,000 principal would generate $1,500 of dividends. As long as all 25 people are alive, each will receive a 1/25th share, or $1,500 / 25 = $60, which is simply equal to a 6% payout on their original $1,000 principal.
However, if after several years only 20 people remain alive, the $1,500 annual dividend (6% of the principal) is now split amongst just those 20 people, resulting in a per-person dividend increase to $1,500 / 20 = $75.
As more people pass away, the tontine payments to the survivors continue to grow (as the same total dividend payment is shared amongst a smaller and smaller pool of people), with the final few participants receiving extraordinarily large dividend payments in their final years (especially relative to their individual investment of only $1,000).