Every quarter, FTX will consider rebalancing its index futures.
We will announce all rebalances at least a day in advance.
Index rebalances will happen over the course of 1 hour. Every 10 seconds we compute a new set of weights, such that at time t the number of tokens of coin in the index is weight_t(coin) = x_t * ((1 - t / (1 hour)) * weight_original(coin) + t / (1 hour) * weight_target(coin)), where the scaling factor x_t is chosen such that the index price computed using weight_t is equal to the index price computed using weight_{t - 10 seconds}.
This will insure that index does not gain or lose value as a consequence of the rebalance.
__________________________________________