Day Trading

The brokerage wouldn't have to do anything. You have to deposit the money into the brokerage account and have cleared funds before you can trade. You would have to use a cash advance or a credit card check to get money to deposit into your brokerage account.

So your estate would owe the credit card company, just the same as if you had run up your credit cards on anything else. The executor of your estate would have to sell something to cover the debts, and the stocks would be a likely a candidate. So really, in the event of your death, the credit card company doesn't have a specific claim on the stocks, but a general claim against all of your assets, before they are disbursed to your heirs.