I have probably said this at least a hundred times and since these days people keep repeating bitcoin share of market cap I though to make this topic, finally!Market capitalization (market cap) is the market value at a point in time of the shares outstanding of a publicly traded company, being equal to the share price at that point of time times the number of shares outstanding.
in cryptocurrency world the "shares" are the number of available coins". and to put simply market cap is calculated by a very simple multiplication of "available coins and price.
Market capitalization, by itself, is NOT a measurement of the value of entityA company set up to run a business will usually have money (and perhaps other assets) put into it by the shareholders in return for an allotment of shares.
a cryptocurrency however can have as many "shares" or "number of available coins" as it wants. because to put simply, it is code and you can put any number you want as the block reward, the initial block reward, the premine, and a whole lot of other methods! and you don't have to worry about taxation and other legal matters than a company faces when they issue a share.
here is how Market capitalization is a bad factor of comparison. (to those who said bitcoin has X% of market cap now):
I can start a new coin today and set the maximum number of coins to a big number, premine the coin to hold a large portion of it myself, add some "interesting features", advertise the coin by spending some money and release it.
lets say I pump the coin to 50K satoshi (it is easily done every day in the altcoin market) in which case I only need about 32 billion coins available
to surpass bitcoin's market cap.
now lets assume I have a lot of money and am a good and experienced pumper and can actually pump my coin up to 0.01
BTC in which case I would only need 1.6 billion coins
to surpass bitcoin's market cap. and so on.
now is my coin really worth more than bitcoin? (see the
example in this comment)
it is worth adding that currently there are 2 coins with 180 and 100 billion "supply" with 2 digits satoshi price. and a total of 12 coins with above billion available supply prices ranging from a couple of satoshis to 21K satoshi and they get pumped so price can go much higher.
finally with altcoin supply two things happen:
1) these available coins are really available to everyone and if it is not well thought and is really big it will crash the price.
as an example I can name Dogecoin. in this case the massive sell pressure (big supply versus a small demand) will crash the price and will always keep it down.
2) these available coins aren't really available. here is where all the manipulations come in. methods like pre-mining the altcoin, things like ICO and so many other ways of taking control of the supply so that the real (available) supply is far less than lists such as
https://coinmarketcap.com show.
as an example I can name ethereum with its (apparently) no max limit coin which currently has 90 million coins available. but is it all really available?