UPDATE: I totally misread the post below, so I am adding some
RED notes to show what has been clarified to me, didn't mean to deceive anyone!
I just found this post
But isn't market cap calculated by price of coin * current price per coin?
Yes number of available coins * price per coin.
What happened BitsharesX has overtaken them on marketcap and they did not like to get past down the rank so they went to the old trickery book and changed the available number of XRP from 8bil to 28bil. Of course there where not 20bil sold at an instant in fact not even the 8bil from before where all sold, so there marketcap was "wrong" to start with. The total sold is somewhere in the millions to date. In this case the correct way to calculate marketcap would be sold coins * price per coin but he wait that is wrong as well because RIPPLE set the price. If you control the coins its not a free market unlike ever other coin.
Overall they (RIPPLE) are literately worse than the FED
and this from before [using google search

]
If you have a look in the client at the assets tab you also find the maximum share supply 10 billion. No idea why this actually is.
>> blockchain_get_asset 0
{
"id": 0,
"symbol": "BTSX",
"name": "BitShares X",
"description": "Decentralized Autonomous Exchange",
"public_data": "",
"issuer_account_id": 0,
"precision": 100000,
"registration_date": "20140719T000000",
"last_update": "20140719T000000",
"current_share_supply": 199998457024777,
"maximum_share_supply": 1000000000000000,
"collected_fees": 16992815762
}
But yes there are never going to be more than 2B BTSX so I wouldn't worry too much about it.
What is the truth, how many BTSX shares are there?
Was it changed?
Is there a non-technical summary of all these changes somewhere? For a simple overview?