Satoshi, the creator of Bitcoin is expected to have many millions of Bitcoins making him the richest Bitcoin millionaire in the world, but there is currently only 1 block that has been confirmed is from Satoshi. On that block (Block 9) there were 50 BTC and they were the first bitcoins ever spent making them (back when nobody used to know about bitcoins) 100% of circulating bitcoins.
So who has those 50 BTC? Taras from Bitcointalk.org did some research and made some interesting discoveries (all credit of both images & info go to Taras). Lets start by taking a look at the Chart bellow (Yellow = Spent and Green = unspent BTC) In order to understand the chart better we have made it smaller then the original
Like mentioned previously, the first block was Block 9 which contained 50 BTC, satoshi sending Hal Finney 10 BTC leaving him with just 40, he then send 12 BTC to an group of people, leaving him with just 28 BTC. The last 10 BTC were send to Bbz, which means that from the 50 there are only 18 BTC left. Lets take a look at the image bellow:
From the original 50, only 6.31 BTC are still circulating today and there is a small chance, your wallet might contain .00001 of the very first circulating bitcoins mined by Satoshi him self.