Liquidity Premium

You pay more for being able to sell something...sooner. That's the liquidity premium.

It used to apply wholly to publicly traded stocks. That is, private companies traded at a discount when investors wanted to invest because they couldn't sell, at least not until the company had gone public and they'd then waited 6 months and change, or something like that.

There was a discount to the pricing of private companies. But then the world changed, with so many investors interested in funding private companies that they no longer roundly trade at a discount with liquid public companies.

Regardless, you can imagine that it's a lot more attractive to invest in something when you know you can click a button and turn that investment into cash quickly, rather than have to wait months or years or decades before having the privilege.