Negative goodwill is a very unusual situation in practice. It happens when Company A buys Company B for less than the net asset value shown in Company B's accounts. Assets in Company B's accounts would have been revalued at the point of the goodwill calculation, so the low price paid by Company A cannot be explained by saying that the assets owned by Company B are simply undervalued in the accounts. Usually it is a distressed sale, and Company B is being bought for a knock-down price. In most circumstances the negative goodwill can be treated as a profit in Company A's consolidated income statement. In the consolidated accounts it would boost the retained profits (referred to more generally as "other reserves" in the course note text).
