Proof of funds from a stock portfolio ?!

[Donald Weyhrauch]

Hello!  Newbie here looking for advice:

While I saved up cash for real estate, I didn't want the money just sitting in a .05% interest rate savings account, so I moved it to a brokerage account and invested in relatively safe large cap stocks to earn a better return than a savings account. I sold off a large chunk of stock to show an "available cash" in my brokerage account when making all cash offers.

Over the past several days the market did great and I lost out on the gains. My question is, can I show a brokerage account value in stock instead of cash? This way it shows I have the money, although it is currently invested in stock, and can easily move that value to cash and transfer to another party within 2 business days. In this way I can still capitalize on market gains and show I have easy to access funds.

Would a seller go for this or does it literally need to be liquid "cash" sitting in a checking account? The stock brokerage I'm using isn't some sort of restricted retirement account with limitations on withdrawals. I don't mind selling off stocks once the title company wants something official.  Can I hand over a statement with 50K value in stock and say "Look I have the cash, it's just in XXXX stock right now."