[rsynnott]

So, it's a bit different. In the simplest case, a company pays 1bn dividends every year, so if 5% is considered a good rate of return currently, and there's no reason to expect the company's profitability changes much, then the value of that company is $20bn. Now, obviously, there's a lot of complexity layered on top of this. Many companies don't do dividends, preferring stock buybacks, for various reasons. Some companies are valued on _assumed future profits_, not current (ie valued on potential). And then there's speculation. But ultimately, if half of the $20bn company is suddenly sold, well, the price, in a rational market, shouldn't actually move much, unless the future value of money has also shifted. The company could be taken private by someone who had $20bn and thought $1bn/year was a good return.

Bitcoin's really pretty different; the value is ~entirely speculation driven. It does not, and cannot, pay dividends, or buy back its own 'shares', or anything like that. No-one would ever consider buying all the bitcoins (in the same way they might take the $20bn company private); the sole value of bitcoin is in other people wanting to buy bitcoin.