Stock is not cash. You can't sell it at the current value price. You can't even sell 0.1% of it without driving the price to zero. The liquidity is just not that large.
This becomes particularly interesting if I can buy $100 of gold bars for $50. Even if I can't sell them, I can use them to my advantage.
My point wasn't that you can turn stock into cash, but that you can turn stock into some of the same things that large amounts of cash might be used for -- acquisitions.
2) Secondly, companies routinely do secondary sales in which they sell stakes of themselves far in excess of 0.1%.
It's rare for a company to do a secondary offering.
That's a keeper!
Liquidity is a high-velocity component to markets. There's more depth that the sub-OP credits the market with at the present instant. But it really can disappear fast. I think there's actually a lot less depth to US equities than most people think, over the long run.