Because it's so exponential, I would imagine a rapid sale of 5% would remove 90% of the value, but I'd love to know the specifics.
The future value of Bitcoin in USD is entirely dependent on people in the future wanting to buy Bitcoin for USD; if no one wants to, it is not worth any USD.
What I would like to know is how much money has actually been transferred into the exchanges. That is what matters. If Coinbase has 12 million accounts, and on average only $100 was invested (I'm assuming there are MANY opened yet unfunded accounts), then we're talking about $1.2billion at play moving back and forth on that exchange. (this is just a hypothetical number, I would love Coinbase to produce statistics, but know they have no incentive to.)
If no new accounts get opened and no more money flows in, That $1.2b will slowly drop to zero as Coinbase and the miners eat up that pool with fees.
No one really notes the "total volume" of the trades of stocks, which is what you're asking for for Bitcoin; it isn't really a meaningful number. If people pass a stock - or a Bitcoin - back and forth for 10 trades for [$99, $101] or for 100 trades for [$99, $101], it isn't really meaningful.
The best you can do for Bitcoin is to try to gauge the "depth of the market" right now, ie, how many "buy" and "sell" orders are out at what prices, how much Bitcoin you could buy or sell right now and what the average price you could buy or sell a large quantity of Bitcoin at. (Eg, if you wanted to sell X Bitcoin, you might be able to sell X/2 Bitcoin at $PRICE and X/2 Bitcoin at $PRICE/2, for an average price of $PRICE*3/4.)
OP is asking about Market Cap not volume.
The question at hand is - market cap vs. money invested by current owners of bitcoin. Hypothesis being that this ratio is high.
That total is almost certainly less than the "market cap".
What does that number tell you? It doesn't tell you the minimum value of a Bitcoin.
Every USD "put into" AAPL is simultaneously taken out by the person on the other side of the trade.
Very few things truly destroy money, and I'm pretty sure all of them are done by banks or treasuries.
Otherwise I can also say the same thing, that you can literally put dollars into Bitcoin by buying GBTC shares, since the dollars become "assets inside" the Bitcoin Investment Trust company.
But what are those assets worth? AAPL owns patents, inventory, raw material, real estate, subsidiaries, investments (stocks, bonds, commodities, T-bills, the whole shebang) and straight-up cash. You can add all those together and you can evaluate each of them based on how their value can change over time and under different market conditions.
What assets does GBTC hold? If the answer is "Bitcoin", you've just recursed on "What is the value of a Bitcoin?"; if the answer is "Bitcoin, cash, other cryptocurrencies, and a whole lot of other assets", great, you can evaluate each of them independently and add them all together. But again, you're recursing on the value of cryptocurrencies without really coming any closer to an answer.
Just the claim that "you can't put dollars into Bitcoin, because there is a seller on the other side which takes the dollars" somehow applies to Bitcoin in a special way. My claim is that this is true for most assets out there, stocks, commodities, or financial contracts.
What do you now own in each case?
AAPL liquidates all of its assets, pays off its debts, and distributes the balance to its former shareholders. You probably don't get $1000, you probably get something like $50 or $100.
Someone delivers some number of physical, frozen pork bellies to you.
And from Bitcoin you get nothing.
This is what I mean when I say all of the buying doesn't actually "put money" into Bitcoin: it is an investment with no underlying value. With all other markets, what you think of as a two-party trade, between the buyer and the seller, is actually a three-party affair, between the buyer, the seller, and the company or asset being traded. "Putting money" into a company ultimately results in that company having more money to build out their business with; "putting money" into a commodity ultimately results in more producers producing more of the commodity. "Putting money" into Bitcoin ultimately results ... in nothing.
One thing we know is that the USD exchange volume for the last 30 days was about $295 billion [0] (or almost 100% of the market cap). However, a lot of this volume is due to the same group of traders circulating the same coins back and forth.
Ultimately and as other commenters pointed out, it doesn't really matter. It is possible that people who bought BTC with "hard earned cash" are statistically more unwilling to sell at a loss but that's about how much you could infer from that statistic in my opinion.
I realize it's not a perfect comparison, but I think it highlights the fact that large sales aren't going to just decimate bitcoin's value.
Given those figures come from the completely unregulated, unaudited, incredibly sketchy exchanges themselves, I would take that with a huge grain of salt. Odds are good a vast majority of that $3 billion is trades using funny money or, for all you know, made up out of thin air. Easy to just trade with yourself all day...
An every day analogy: saying a river can never flood because there it has a big dam.