The market isn't sufficiently well developed and doesn't have sufficient depth to support transactions of that size. Combine a lack of liquidity with the fact that BTC have no intrinsic value, and that the market has shown itself to be vulnerable to price shocks in the past, and I would value 1M BTC at significantly less than $1B (probably not even 10% of that).
Conversely, it seems unlikely that e.g. Google's shares would be worth the current market cap if they were all sold at the same time. But we still accept the current share price as a basis of e.g. Page and Brin's net worth, so we should also accept Satoshi's wallet's current value (even if it fluctuates more than typical stock prices).
Not really true. Google's shares have a value that is based mostly on analysis of expected value. If they offloaded a bunch of their shares at once, the analyzed value wouldn't change, so the market would only crash for a very short time while everyone else realizes Google is a better deal than their other stocks.
There is no revenue from Bitcoin, on the other hand. Much like gold, its value is almost entirely based on speculation, but with some added value on account of people needing to buy a little bit to do certain things. The market cap of Bitcoin is not based on anything tangible.
You're assuming: 1. That it would be a block transaction, where a block doesn't refer to a BTC block but a single transaction. Most institutional/sophisticated/smart traders scale out of their positions. 2. There may be an underlying assumption that just because someone (satoshi etc.) sell their bitcoin's for X price they would want to withdraw it in another currency. If the goal is to own more BTC, they would transfer in BTC to a trading account, sell said BTC while scaling out and buy back BTC when prices drop below their average sell price.
If someone was extremely cautious they would do these trades under multiple accounts, most BTC trading accounts need verification for deposits/withdrawal only. This could be done on multiple exchanges.
The average weekly trading volume of mtgox is >130,000BTC/week, therefore over 7 million BTC were traded which is sufficient volume to liquidate 70-100% of 1M BTC.
Doesn't collateral require that you provide the ability to transfer ownership?
Basically, that wallet should be used to nurture and feed the bitcoin ecosystem, and in doing so it can become worth vastly more. It becomes the JP Morgan - circa 1910 - of the bitcoin financial world. With the profit generated from the business, it can be used to calm panics, and help lessen volatility, a form of pressure regulator.
Even today's $1k BTC is speculation at the edge of the market, 1million BTC as a batch only fetch about $50m worth of interested buyers.
Here is one ting I don't understand, though: suppose I am a billionaire black hat VC, and I wanted to steal Satoshi's coins. Could I invest a half billion dollars and brute force a majority-coup attack on the blockchain? Of not now what about when those $ figures are 10x? Even if bitcoin gets 100x more popular, it won't be 100x more network miners, it will be people buying BTC and trusting the block chain published by coinbase and whoever.
Further, performing this attack would invalidate all Bitcoins created after that point (which is the vast majority of them), so the Bitcoins you stole would be worthless.
A 50+% attack operates by rewriting history back to a certain depth in the blockchain by providing a new chain of blocks with more computational work, back to a certain point.
I think the bitcoin devs also put in certain "checkpoints" just to be even more certain... i.e. blocks that are "officially permanent" (which also makes all prior blocks in that chain "offiically permanent").
Maybe someone could tell us about that.
No - controlling a majority of the compute doesn't allow you to steal some unrelated users bitcoins.
You'd have to brute force their private key to do that, which is an infeasible computational challenge.
Controlling a majority of the compute would allow you to 'double spend' coins you have, but that's a different problem.
There are other methods of selling coins. Larger transactions tend to happen off-exchange.