The CLDR defines US negative currencies, and perhaps others, as using parenthesis, like you'd see in accounting! This should parse, though I admit it's not what people expect. We may have to revisit that. You should be able to override this by defining a number format with the positive expression and a negative expression separated by a semi-colon, e.g. *#.##;-*#.## where * is \ua4 or the international currency symbol.