If it says 100 million shares issued, then that is self explanatory, but shares if bought out of a private placement often are accompanied by warrants in the order of the same volume if 1 to1 or 1 for 2 and for a period of 1 or 2 years depending on how its written up. Those warrants may or may not be purchased at their guaranteed price but if they are purchased then there is a potential for another 16 million shares. Thats what full diluted means. It also includes Options .