hi5, That seems interesting. Vyalentine deen samma fursad chaina- tesaile ahile lai- if you've already not googled, i found some vba snippets at http://www.vbnumericalmethods.com/vbnumericalmethods/download.asp?codeType=m&cTitle=Normal%20Inverse%20Gaussian%20Random%20Number%20Generator I used @risk (TM) software (Excel application software) to generate all sorts of distribution for my use but it was not a freeware, and more than that it needed a dongle key. Lou, joyNepal.