When we say that something has "bottomed out," we usually mean that it has reached its minimum level or point of decline. The opposite of bottoming out is reaching a peak, soaring, or thriving. For example, a stock that has bottomed out may eventually start to rise again, or a business that has hit bottom may find ways to improve and grow. Other antonyms for bottomed out might include rebounding, recovering, or bouncing back. Essentially, any word that implies a positive trend or upward movement can be seen as an antonym of bottoming out.