The growing number of companies leaping into the same day delivery fray suggests that retailers specifically are worried about missing out on a piece of the consumer interest if the current ceiling for same day carrier options is higher than expected. There's every chance that the battle will see some services come and go and the deciding factor will most likely rest with the consumer adoption rates from city to city. Department store Macy's are the latest to launch a same day delivery option so we'll keep an eye on their overall expansion.