Antonyms for "mounting to" include "decreasing to," "falling to," "reducing to," and "shrinking to." These terms imply a decrease in value, prominence or significance. For example, if someone's debt were to "mount to" $10,000, it would imply an increase in debt. However, if the debt were to "fall to" $5,000, it would imply that the debtor has paid off some of the outstanding amount. Similarly, if a company's profits were to "mount to" $1 million, it would imply growth, whereas if they were to "shrink to" $500,000, it would imply a decline.