Subscribe to The Chicago Manual of Style Online
Q. Our company has always presented costs to clients in both written and numerical form. For example, “The cost for our services is two thousand one hundred fifty dollars ($2,150).” One client has pointed out that the number in parentheses is negative and therefore we owe him money. How can we present numbers to clients in both written and numerical form without using the parentheses, which may indicate a negative number?
A. Parentheses are occasionally used instead of the minus sign in tabular matter (e.g., spreadsheets) to indicate negative quantities. In most contexts, however, parentheses set off text that explains or qualifies or amplifies the surrounding context—as in your example and often in contracts and other legal documents. Parentheses used in this way have no bearing on any quantities they enclose—monetary or otherwise. Continue presenting your costs as you always have.