After the contract, any increase belongs to the wife, since the ṣadâq is now her property in its entirety (regardless of who is actually in possession of it). If she needs to return half of it because a divorce takes place before the consummation, she returns half of the original ṣadâq, keeping the other half as well as any growth/profit that emanated from it. If this growth can easily be separated from the original ṣadâq, such as in the case of livestock giving birth, then she returns half of the livestock he gave her, and she keeps the other half, along with all of the newborns. If the gain of the original ṣadâq is not easily separated from the original, such as when livestock gain weight, she has the option of returning half of the value of the original ṣadâq or half of the existing (fatter) livestock.
In the case of decrease:
If the woman demands the ṣadâq but the man procrastinates, and then the value of the ṣadâq is diminished or completely wiped out, he is liable for it. This means that if divorce happens after the contract but before consummation, he will have to pay her half of the original value of that ṣadâq.
If she does not request it, then it is in his possession as a trust, and the rulings of trusts will apply. He is only liable for the loss if it results from negligence or wrongdoing on his part.
If she receives it, and then it is diminished or completely lost, she is liable. In the case of divorce before consummation, she must return to him half of the original value of the ṣadâq, unless he agrees to taking half of the diminished Ṣadâq (like an emaciated cow).