[mrb]

I make a living trading BTC. I know the difference.

The OP mentioned selling in a day, not at once: «I doubt you could liquidate millions of dollars of bitcoin IN A DAY...» This is what I commented on.

You changed the topic and started talking about selling all at once, which would of course eat a bunch of bids. However even doing this wouldn't "crash the market." The order books are deeper than you think. It's hard to find examples, because it's plain dumb to market-sell this much in one order. But I found a ~1150 BTC sell on Bitstamp around 3pm on September 13 and it barely moved the price: https://bitcoincharts.com/charts/bitstampUSD#rg5zig1-minzczs...

It would eat even lower bids on exchanges with less volume/thinner books, but still wouldn't crash the market. For example some idiot sold 1200 BTC in two market-sells of 600 BTC each, 30min apart yesterday on Gemini; and although it ate all the bids from $4100 to $3400, twice!, it didn't "crash the market". Other exchanges didn't react. Subsequent trades resumed exactly where the price was before ($4100).

[gnaritas]

OK, little more liquid than I expected, I just glanced at the order books on bitcoinwisdom. What happened on Gemini looks more what I'd expect, a deep and fast crash as all the liquidity was eaten.