When formatting a currency for display, always use a CultureInfo object when outputting in order to get the correct formatting – different places will have a different thousands separator, decimal separator and more.
In many cases, you can get the CultureInfo from the UI thread and in a web application you could guess which one is the correct one, by parsing out the user agent header.
If you always want the exact same output, you do not have to specify a format string, simply use CultureInfo.InvariantCulture, this is a dummy culture and does not correspond to any country/region. The different settings are similar to “en-US”.
This example will output the format for the Swedish culture.
decimal value = -16325.62m; Console.WriteLine(value.ToString(CultureInfo.CreateSpecificCulture("sv-SE")));
This example will output the format for the InvariantCulture.
decimal value = -16325.62m; Console.WriteLine(value.ToString(CultureInfo.InvariantCulture));
Here is a list of culture names.