Examples of Negative Value Formatting
Since the number format is based on Java formatters, you can use a semi-colon (;) sub-pattern boundary to represent negative numbers so that they stand out differently from positive values.
The following examples show how to use the semi-colon to represent the negative value, -1234.56.
#,##0.00;(#,##0.00) displays the value, -1234.56, as (1,234.56)
#,##0.00;'<font color=red>'(#,##0.00) displays the value, -1234.56, in red as (1,234.56)